CHANGELOG.md

 * fix(discriminator): allow user-defined discriminator path in schema #7807
 * fix(query): ensure `findOneAndReplace()` sends `replacement` to server #7654
 * fix(cast): allow `[]` as a value when casting `$nin` #7806
 * docs(model): clarify that setters do run on `update()` by default #7801
 * docs: fix typo in FAQ #7821 [jaona](https://github.com/jaona)

5.5.9 / 2019-05-16
==================
 * fix(query): skip schema setters when casting $regexp $options #7802 [Fonger](https://github.com/Fonger)
 * fix(populate): don't skip populating doc array properties whose name conflicts with an array method #7782
 * fix(populate): make populated virtual return undefined if not populated #7795
 * fix(schema): handle custom setters in arrays of document arrays #7804 [Fonger](https://github.com/Fonger)
 * docs(tutorials): add query casting tutorial #7789

5.5.8 / 2019-05-13
==================
 * fix(document): run pre save hooks on nested child schemas #7792
 * fix(model): set $session() before validation middleware for bulkWrite/insertMany #7785 #7769 [Fonger](https://github.com/Fonger)
 * fix(query): make `getPopulatedPaths()` return deeply populated paths #7757
 * fix(query): suppress findAndModify deprecation warning when using `Model.findOneAndUpdate()` #7794
 * fix: upgrade mongodb -> 3.2.4 #7794
 * fix(document): handle a couple edge cases with atomics that happen when schema defines an array property named 'undefined' #7756
 * docs(discriminator): correct function parameters #7786 [gfpacheco](https://github.com/gfpacheco)

5.5.7 / 2019-05-09
==================
 * fix(model): set $session() before pre save middleware runs when calling save() with options #7742
 * fix(model): set $session before pre remove hooks run when calling remove() with options #7742
 * fix(schema): support `remove()` on nested path #2398
 * fix(map): handle setting populated map element to doc #7745
 * fix(query): return rawResult when inserting with options `{new:false,upsert:true,rawResult:true}` #7774 #7770 [LiaanM](https://github.com/LiaanM)
 * fix(schematype): remove internal `validators` option because it conflicts with Backbone #7720

5.5.6 / 2019-05-06
==================
 * fix(document): stop converting arrays to objects when setting non-schema path to array with strict: false #7733
 * fix(array): make two Mongoose arrays `assert.deepEqual()` each other if they have the same values #7700
 * fix(populate): support populating a path in a document array embedded in an array #7647
 * fix(populate): set populate virtual count to 0 if local field is empty #7731
 * fix(update): avoid throwing cast error if casting array filter that isn't in schema with strictQuery = false #7728
 * docs: fix typo in `distinct()` description #7767 [phil-r](https://github.com/phil-r)

5.5.5 / 2019-04-30
==================
 * fix(document): ensure nested properties within single nested subdocs get set correctly when overwriting single nested subdoc #7748
 * fix(document): skip non-object `validators` in schema types #7720
 * fix: bump mongodb driver -> 3.2.3 #7752
 * fix(map): disallow setting map key with special properties #7750 [Fonger](https://github.com/Fonger)

5.5.4 / 2019-04-25
==================
 * fix(document): avoid calling custom getters when saving #7719
 * fix(timestamps): handle child schema timestamps correctly when reusing child schemas #7712
 * fix(query): pass correct callback for _legacyFindAndModify #7736 [Fonger](https://github.com/Fonger)
 * fix(model+query): allow setting `replacement` parameter for `findOneAndReplace()` #7654
 * fix(map): make `delete()` unset the key in the database #7746 [Fonger](https://github.com/Fonger)
 * fix(array): use symbol for `_schema` property to avoid confusing deep equality checks #7700
 * fix(document): prevent `depopulate()` from removing fields with empty array #7741 #7740 [Fonger](https://github.com/Fonger)
 * fix: make `MongooseArray#includes` support ObjectIds #7732 #6354 [hansemannn](https://github.com/hansemannn)
 * fix(document): report correct validation error index when pushing onto doc array #7744 [Fonger](https://github.com/Fonger)

5.5.3 / 2019-04-22
==================
 * fix: add findAndModify deprecation warning that references the useFindAndModify option #7644
 * fix(document): handle pushing a doc onto a discriminator that contains a doc array #7704
 * fix(update): run setters on array elements when doing $set #7679
 * fix: correct usage of arguments while buffering commands #7718 [rzymek](https://github.com/rzymek)
 * fix(document): avoid error clearing modified subpaths if doc not defined #7715 [bitflower](https://github.com/bitflower)
 * refactor(array): move `_parent` property behind a symbol #7726 #7700
 * docs(model): list out all operations and options for `bulkWrite()` #7055
 * docs(aggregate): use `eachAsync()` instead of nonexistent `each()` #7699
 * docs(validation): add CastError validation example #7514
 * docs(query+model): list out all options and callback details for Model.updateX() and Query#updateX() #7646

5.5.2 / 2019-04-16
==================
 * fix(document): support setting nested path to non-POJO object #7639
 * perf(connection): remove leaked event handler in `Model.init()` so `deleteModel()` frees all memory #7682
 * fix(timestamps): handle custom statics that conflict with built-in functions (like mongoose-delete plugin) #7698
 * fix(populate): make `Document#populated()` work for populated subdocs #7685
 * fix(document): support `.set()` on document array underneath embedded discriminator path #7656

5.5.1 / 2019-04-11
==================
 * fix(document): correctly overwrite all properties when setting a single nested subdoc #7660 #7681
 * fix(array): allow customization of array required validator #7696 [freewil](https://github.com/freewil)
 * fix(discriminator): handle embedded discriminators when casting array defaults #7687
 * fix(collection): ensure collection functions return a promise even if disconnected #7676
 * fix(schematype): avoid indexing properties with `{ unique: false, index: false }` #7620
 * fix(aggregate): make `Aggregate#model()` with no arguments return the aggregation's model #7608

5.5.0 / 2019-04-08
==================
 * feat(model): support applying hooks to custom static functions #5982
 * feat(populate): support specifying a function as `match` #7397
 * perf(buffer): avoid calling `defineProperties()` in Buffer constructor #7331
 * feat(connection): add `plugin()` for connection-scoped plugins #7378
 * feat(model): add Model#deleteOne() and corresponding hooks #7538
 * feat(query): support hooks for `Query#distinct()` #5938
 * feat(model): print warning when calling create() incorrectly with a session #7535
 * feat(document): add Document#isEmpty() and corresponding helpers for nested paths #5369
 * feat(document): add `getters` option to Document#get() #7233
 * feat(query): add Query#projection() to get or overwrite the current projection #7384
 * fix(document): set full validator path on validatorProperties if `propsParameter` set on validator #7447
 * feat(document): add Document#directModifiedPaths() #7373
 * feat(document): add $locals property #7691
 * feat(document): add validateUpdatedOnly option that only validates modified paths in `save()` #7492 [captaincaius](https://github.com/captaincaius)
 * chore: upgrade MongoDB driver to v3.2.0 #7641
 * fix(schematype): deprecate `isAsync` option for custom validators #6700
 * chore(mongoose): deprecate global.MONGOOSE_DRIVER_PATH so we can be webpack-warning-free in 6.0 #7501

5.4.23 / 2019-04-08
===================
 * fix(document): report cast error when string path in schema is an array in MongoDB #7619
 * fix(query): set deletedCount on result of remove() #7629
 * docs(subdocs): add note about parent() and ownerDocument() to subdocument docs #7576

5.4.22 / 2019-04-04
===================
 * fix(aggregate): allow modifying options in pre('aggregate') hook #7606
 * fix(map): correctly init maps of maps when loading from MongoDB #7630
 * docs(model+query): add `omitUndefined` option to docs for updateX() and findOneAndX() #3486
 * docs: removed duplicate Query.prototype.merge() reference from doc #7684 [shihabmridha](https://github.com/shihabmridha)
 * docs(schema): fix shardKey type to object instead of bool #7668 [kyletsang](https://github.com/kyletsang)
 * docs(api): fix `Model.prototypedelete` link #7665 [pixcai](https://github.com/pixcai)

5.4.21 / 2019-04-02
===================
 * fix(updateValidators): run update validators correctly on Decimal128 paths #7561
 * fix(update): cast array filters in nested doc arrays correctly #7603
 * fix(document): allow .get() + .set() with aliased paths #7592
 * fix(document): ensure custom getters on single nested subdocs don't get persisted if toObject.getters = true #7601
 * fix(document): support setting subdoc path to subdoc copied using object rest `{...doc}` #7645
 * docs(schema): correct out-of-date list of reserved words #7593
 * docs(model+query): add link to update results docs and examples of using results of updateOne(), etc. #7582
 * docs: use atomic as opposed to $atomic consistently #7649 [720degreeLotus](https://github.com/720degreeLotus)

5.4.20 / 2019-03-25
===================
 * docs(tutorials): add tutorial about `lean()` #7640
 * fix(discriminator): fix wrong modelName being used as value to partialFilterExpression index #7635 #7634 [egorovli](https://github.com/egorovli)
 * fix(document): allow setters to modify `this` when overwriting single nested subdoc #7585
 * fix(populate): handle count option correctly with multiple docs #7573
 * fix(date): support declaring min/max validators as functions #7600 [ChienDevIT](https://github.com/ChienDevIT)
 * fix(discriminator): avoid projecting in embedded discriminator if only auto-selected path is discriminator key #7574
 * fix(discriminator): use discriminator model when using `new BaseModel()` with discriminator key #7586
 * fix(timestamps): avoid throwing if doc array has timestamps and array is undefined #7625 [serg33v](https://github.com/serg33v)
 * docs(document): explain DocumentNotFoundError in save() docs #7580
 * docs(query): fix .all() param type and add example #7612 [720degreeLotus](https://github.com/720degreeLotus)
 * docs: add useNewUrlParser to mongoose.connect for some pages #7615 [YC](https://github.com/YC)

5.4.19 / 2019-03-11
===================
 * fix(mongoose): ensure virtuals set on subdocs in global plugins get applied #7572
 * docs(tutorials): add "Working With Dates" tutorial #7597
 * docs(guide): clarify that versioning only affects array fields #7555
 * docs(model): list out all bulkWrite() options #7550

5.4.18 / 2019-03-08
===================
 * fix(document): handle nested virtuals in populated docs when parent path is projected out #7491
 * fix(model): make subclassed models handle discriminators correctly #7547
 * fix(model): remove $versionError from save options for better debug output #7570

5.4.17 / 2019-03-03
===================
 * fix(update): handle all positional operator when casting array filters #7540
 * fix(populate): handle populating nested path where top-level path is a primitive in the db #7545
 * fix(update): run update validators on array filters #7536
 * fix(document): clean modified subpaths when sorting an array #7556
 * fix(model): cast $setOnInsert correctly with nested docs #7534
 * docs: remove extra curly brace from example #7569 [kolya182](https://github.com/kolya182)

5.4.16 / 2019-02-26
===================
 * fix(schema): handle nested objects with `_id: false` #7524
 * fix(schema): don't throw error if declaring a virtual that starts with a map path name #7464
 * fix(browser): add stubbed `model()` function so code that uses model doesn't throw #7541 [caub](https://github.com/caub)
 * fix(schema): merge virtuals correctly #7563 [yoursdearboy](https://github.com/yoursdearboy)
 * docs(connections): add reconnectFailed to connection docs #7477
 * docs(index): fix typo #7553 [DenrizSusam](https://github.com/DenrizSusam)
 * refactor(schema): iterate over paths instead of depending on childSchemas #7554

5.4.15 / 2019-02-22
===================
 * fix(update): don't call schematype validators on array if using $pull with runValidators #6971
 * fix(schema): clone all schema types when cloning an array #7537
 * docs(connections): improve connectTimeoutMS docs and socketTimeoutMS docs to link to Node.js net.setTimeout() #5169
 * docs: fix setters example in migration guide #7546 [freewil](https://github.com/freewil)

5.4.14 / 2019-02-19
===================
 * fix(populate): make `getters` option handle nested paths #7521
 * fix(documentarray): report validation errors that occur in an array subdoc created using `create()` and then `set()` #7504
 * docs(schema): add examples for schema functions that didn't have any #7525
 * docs: add MongooseError to API docs and add list of error names
 * docs(CONTRIBUTING): fix link #7530 [sarpik](https://github.com/sarpik)

5.4.13 / 2019-02-15
===================
 * fix(query): throw handy error when using updateOne() with overwrite: true and no dollar keys #7475
 * fix(schema): support inheriting existing schema types using Node.js `util.inherits` like mongoose-float #7486
 * docs(connections): add list of connection events #7477

5.4.12 / 2019-02-13
===================
 * fix(connection): dont emit reconnected due to socketTimeoutMS #7452
 * fix(schema): revert check for `false` schema paths #7516 #7512
 * fix(model): don't delete unaliased keys in translateAliases #7510 [chrischen](https://github.com/chrischen)
 * fix(document): run single nested schematype validator if nested path has a default and subpath is modified #7493
 * fix(query): copy mongoose options when using `Query#merge()` #1790
 * fix(timestamps): don't call createdAt getters when setting updatedAt on new doc #7496
 * docs: improve description of ValidationError #7515 [JulioJu](https://github.com/JulioJu)
 * docs: add an asterisk before comment, otherwise the comment line is not generated #7513 [JulioJu](https://github.com/JulioJu)

5.4.11 / 2019-02-09
===================
 * fix(schema): handle `_id: false` in schema paths as a shortcut for setting the `_id` option to `false` #7480
 * fix(update): handle $addToSet and $push with ObjectIds and castNonArrays=false #7479
 * docs(model): document `session` option to `save()` #7484
 * chore: fix gitignore syntax #7498 [JulioJu](https://github.com/JulioJu)
 * docs: document that Document#validateSync returns ValidationError #7499
 * refactor: use consolidated `isPOJO()` function instead of constructor checks #7500

5.4.10 / 2019-02-05
===================
 * docs: add search bar and /search page #6706
 * fix: support dotted aliases #7478 [chrischen](https://github.com/chrischen)
 * fix(document): copy atomics when setting document array to an existing document array #7472
 * chore: upgrade to mongodb driver 3.1.13 #7488
 * docs: remove confusing references to executing a query "immediately" #7461
 * docs(guides+schematypes): link to custom schematypes docs #7407

5.4.9 / 2019-02-01
==================
 * fix(document): make `remove()`, `updateOne()`, and `update()` use the document's associated session #7455
 * fix(document): support passing args to hooked custom methods #7456
 * fix(document): avoid double calling single nested getters on `toObject()` #7442
 * fix(discriminator): handle global plugins modifying top-level discriminator options with applyPluginsToDiscriminators: true #7458
 * docs(documents): improve explanation of documents and use more modern syntax #7463
 * docs(middleware+api): fix a couple typos in examples #7474 [arniu](https://github.com/arniu)

5.4.8 / 2019-01-30
==================
 * fix(query): fix unhandled error when casting object in array filters #7431
 * fix(query): cast query $elemMatch to discriminator schema if discriminator key set #7449
 * docs: add table of contents to all guides #7430

5.4.7 / 2019-01-26
==================
 * fix(populate): set `populated()` when using virtual populate #7440
 * fix(discriminator): defer applying plugins to embedded discriminators until model compilation so global plugins work #7435
 * fix(schema): report correct pathtype underneath map so setting dotted paths underneath maps works #7448
 * fix: get debug from options using the get helper #7451 #7446 [LucGranato](https://github.com/LucGranato)
 * fix: use correct variable name #7443 [esben-semmle](https://github.com/esben-semmle)
 * docs: fix broken QueryCursor link #7438 [shihabmridha](https://github.com/shihabmridha)

5.4.6 / 2019-01-22
==================
 * fix(utils): make minimize leave empty objects in arrays instead of setting the array element to undefined #7322
 * fix(document): support passing `{document, query}` options to Schema#pre(regex) and Schema#post(regex) #7423
 * docs: add migrating to 5 guide to docs #7434
 * docs(deprecations): add instructions for fixing `count()` deprecation #7419
 * docs(middleware): add description and example for aggregate hooks #7402

4.13.18 / 2019-01-21
====================
 * fix(model): handle setting populated path set via `Document#populate()` #7302
 * fix(cast): backport fix from #7290 to 4.x

5.4.5 / 2019-01-18
==================
 * fix(populate): handle nested array `foreignField` with virtual populate #7374
 * fix(query): support not passing any arguments to `orFail()` #7409
 * docs(query): document what the resolved value for `deleteOne()`, `deleteMany()`, and `remove()` contains #7324
 * fix(array): allow opting out of converting non-arrays into arrays with `castNonArrays` option #7371
 * fix(query): ensure updateOne() doesnt unintentionally double call Schema#post(regexp) #7418

5.4.4 / 2019-01-14
==================
 * fix(query): run casting on arrayFilters option #7079
 * fix(document): support skipping timestamps on save() with `save({ timestamps: false })` #7357
 * fix(model): apply custom where on `Document#remove()` so we attach the shardKey #7393
 * docs(mongoose): document `mongoose.connections` #7338

5.4.3 / 2019-01-09
==================
 * fix(populate): handle `count` option when using `Document#populate()` on a virtual #7380
 * fix(connection): set connection state to DISCONNECTED if replica set has no primary #7330
 * fix(mongoose): apply global plugins to schemas nested underneath embedded discriminators #7370
 * fix(document): make modifiedPaths() return nested paths 1 level down on initial set #7313
 * fix(plugins): ensure sharding plugin works even if ObjectId has a `valueOf()` #7353

5.4.2 / 2019-01-03
==================
 * fix(document): ensure Document#updateOne() returns a query but still calls hooks #7366
 * fix(query): allow explicitly projecting out populated paths that are automatically projected in #7383
 * fix(document): support setting `flattenMaps` option for `toObject()` and `toJSON()` at schema level #7274
 * fix(query): handle merging objectids with `.where()` #7360
 * fix(schema): copy `.base` when cloning #7377
 * docs: remove links to plugins.mongoosejs.com in favor of plugins.mongoosejs.io #7364

5.4.1 / 2018-12-26
==================
 * fix(document): ensure doc array defaults get casted #7337
 * fix(document): make `save()` not crash if nested doc has a property 'get' #7316
 * fix(schema): allow using Schema.Types.Map as well as Map to declare a map type #7305
 * fix(map): make set after init mark correct path as modified #7321
 * fix(mongoose): don't recompile model if same collection and schema passed in to `mongoose.model()` #5767
 * fix(schema): improve error message when type is invalid #7303
 * fix(schema): add `populated` to reserved property names #7317
 * fix(model): don't run built-in middleware on custom methods and ensure timestamp hooks don't run if children don't have timestamps set #7342
 * docs(schematypes): clarify that you can add arbitrary options to a SchemaType #7340
 * docs(mongoose): clarify that passing same name+schema to `mongoose.model()` returns the model #5767
 * docs(index): add useNewUrlParser to example #7368 [JIBIN-P](https://github.com/JIBIN-P)
 * docs(connection): add useNewUrlParser to examples #7362 [JIBIN-P](https://github.com/JIBIN-P)
 * docs(discriminators): add back missing example from 'recursive embedded discriminators section' #7349
 * docs(schema): improve docs for string and boolean cast() #7351

5.4.0 / 2018-12-14
==================
 * feat(schematype): add `SchemaType.get()`, custom getters across all instances of a schematype #6912
 * feat(schematype): add `SchemaType.cast()`, configure casting for individual schematypes #7045
 * feat(schematype): add `SchemaType.checkRequired()`, configure what values pass `required` check for a schematype #7186 #7150
 * feat(model): add `Model.findOneAndReplace()` #7162
 * feat(model): add `Model.events` emitter that emits all `error`'s that occur with a given model #7125
 * feat(populate): add `count` option to populate virtuals, support returning # of populated docs instead of docs themselves #4469
 * feat(aggregate): add `.catch()` helper to make aggregations full thenables #7267
 * feat(query): add hooks for `deleteOne()` and `deleteMany()` #7195
 * feat(document): add hooks for `updateOne()` #7133
 * feat(query): add `Query#map()` for synchronously transforming results before post middleware runs #7142
 * feat(schema): support passing an array of objects or schemas to `Schema` constructor #7218
 * feat(populate): add `clone` option to ensure multiple docs don't share the same populated doc #3258
 * feat(query): add `Query#maxTimeMS()` helper #7254
 * fix(query): deprecate broken `Aggregate#addCursorFlag()` #7120
 * docs(populate): fix incorrect example #7335 [zcfan](https://github.com/zcfan)
 * docs(middleware): add `findOneAndDelete` to middleware list #7327 [danielkesselberg](https://github.com/danielkesselberg)

5.3.16 / 2018-12-11
===================
 * fix(document): handle `__proto__` in queries #7290
 * fix(document): use Array.isArray() instead of checking constructor name for arrays #7290
 * docs(populate): add section about what happens when no document matches #7279
 * fix(mongoose): avoid crash on `import mongoose, {Schema} from 'mongoose'` #5648

5.3.15 / 2018-12-05
===================
 * fix(query): handle `orFail()` with `findOneAndUpdate()` and `findOneAndDelete()` #7297 #7280
 * fix(document): make `save()` succeed if strict: false with a `collection` property #7276
 * fix(document): add `flattenMaps` option for toObject() #7274
 * docs(document): document flattenMaps option #7274
 * fix(populate): support populating individual subdoc path in document array #7273
 * fix(populate): ensure `model` option overrides `refPath` #7273
 * fix(map): don't call subdoc setters on init #7272
 * fix(document): use internal get() helper instead of lodash.get to support `null` projection param #7271
 * fix(document): continue running validateSync() for all elements in doc array after first error #6746

5.3.14 / 2018-11-27
===================
 * docs(api): use `openUri()` instead of legacy `open()` #7277 [artemjackson](https://github.com/artemjackson)
 * fix(document): don't mark date underneath single nested as modified if setting to string #7264
 * fix(update): set timestamps on subdocs if not using $set with no overwrite #7261
 * fix(document): use symbol instead of `__parent` so user code doesn't conflict #7230
 * fix(mongoose): allow using `mongoose.model()` without context, like `import {model} from 'mongoose'` #3768

5.3.13 / 2018-11-20
===================
 * fix: bump mongodb driver -> 3.1.10 #7266
 * fix(populate): support setting a model as a `ref` #7253
 * docs(schematype): add ref() function to document what is a valid `ref` path in a schematype #7253
 * fix(array): clean modified subpaths when calling `splice()` #7249
 * docs(compatibility): don't show Mongoose 4.11 as compatible with MongoDB 3.6 re: MongoDB's official compatibility table #7248 [a-harrison](https://github.com/a-harrison)
 * fix(document): report correct validation error if doc array set to primitive #7242
 * fix(mongoose): print warning when including server-side lib with jest jsdom environment #7240

5.3.12 / 2018-11-13
===================
 * docs(compatibility): don't show Mongoose 4.11 as compatible with MongoDB 3.6 re: MongoDB's official compatibility table #7238 [a-harrison](https://github.com/a-harrison)
 * fix(populate): use `instanceof` rather than class name for comparison #7237 [ivanseidel](https://github.com/ivanseidel)
 * docs(api): make options show up as a nested list #7232
 * fix(document): don't mark array as modified on init if doc array has default #7227
 * docs(api): link to bulk write result object in `bulkWrite()` docs #7225

5.3.11 / 2018-11-09
===================
 * fix(model): make parent pointers non-enumerable so they don't crash JSON.stringify() #7220
 * fix(document): allow saving docs with nested props with '.' using `checkKeys: false` #7144
 * docs(lambda): use async/await with lambda example #7019

5.3.10 / 2018-11-06
===================
 * fix(discriminator): support reusing a schema for multiple discriminators #7200
 * fix(cursor): handle `lean(false)` correctly with query cursors #7197
 * fix(document): avoid manual populate if `ref` not set #7193
 * fix(schema): handle schema without `.base` for browser build #7170
 * docs: add further reading section

5.3.9 / 2018-11-02
==================
 * fix: upgrade bson dep -> 1.1.0 to match mongodb-core #7213 [NewEraCracker](https://github.com/NewEraCracker)
 * docs(api): fix broken anchor link #7210 [gfranco93](https://github.com/gfranco93)
 * fix: don't set parent timestamps because a child has timestamps set to false #7203 #7202 [lineus](https://github.com/lineus)
 * fix(document): run setter only once when doing `.set()` underneath a single nested subdoc #7196
 * fix(document): surface errors in subdoc pre validate #7187
 * fix(query): run default functions after hydrating the loaded document #7182
 * fix(query): handle strictQuery: 'throw' with nested path correctly #7178
 * fix(update): update timestamps on replaceOne() #7152
 * docs(transactions): add example of aborting a transaction #7113

5.3.8 / 2018-10-30
==================
 * fix: bump mongodb driver -> 3.1.8 to fix connecting to +srv uri with no credentials #7191 #6881 [lineus](https://github.com/lineus)
 * fix(document): sets defaults correctly in child docs with projection #7159
 * fix(mongoose): handle setting custom type on a separate mongoose global #7158
 * fix: add unnecessary files to npmignore #7157
 * fix(model): set session when creating new subdoc #7104

5.3.7 / 2018-10-26
==================
 * fix(browser): fix buffer usage in browser build #7184 #7173 [lineus](https://github.com/lineus)
 * fix(document): make depopulate() work on populate virtuals and unpopulated docs #7180 #6075 [lineus](https://github.com/lineus)
 * fix(document): only pass properties as 2nd arg to custom validator if `propsParameter` set #7145
 * docs(schematypes): add note about nested paths with `type` getting converted to mixed #7143
 * fix(update): run update validators on nested doc when $set on an array #7135
 * fix(update): copy exact errors from array subdoc validation into top-level update validator error #7135

5.3.6 / 2018-10-23
==================
 * fix(cursor): fix undefined transforms error

5.3.5 / 2018-10-22
==================
 * fix(model): make sure versionKey on `replaceOne()` always gets set at top level to prevent cast errors #7138
 * fix(cursor): handle non-boolean lean option in `eachAsync()` #7137
 * fix(update): correct cast update that overwrites a map #7111
 * fix(schema): handle arrays of mixed correctly #7109
 * fix(query): use correct path when getting schema for child timestamp update #7106
 * fix(document): make `$session()` propagate sessions to child docs #7104
 * fix(document): handle user setting `schema.options.strict = 'throw'` #7103
 * fix(types): use core Node.js buffer prototype instead of safe-buffer because safe-buffer is broken for Node.js 4.x #7102
 * fix(document): handle setting single doc with refPath to document #7070
 * fix(model): handle array filters when updating timestamps for subdocs #7032

5.3.4 / 2018-10-15
==================
 * fix(schema): make `add()` and `remove()` return the schema instance #7131 [lineus](https://github.com/lineus)
 * fix(query): don't require passing model to `cast()` #7118
 * fix: support `useFindAndModify` as a connection-level option #7110 [lineus](https://github.com/lineus)
 * fix(populate): handle plus path projection with virtual populate #7050
 * fix(schema): allow using ObjectId type as schema path type #7049
 * docs(schematypes): elaborate on how schematypes relate to types #7049
 * docs(deprecations): add note about gridstore deprecation #6922
 * docs(guide): add storeSubdocValidationError option to guide #6802

5.3.3 / 2018-10-12
==================
 * fix(document): enable storing mongoose validation error in MongoDB by removing `$isValidatorError` property #7127
 * docs(api): clarify that aggregate triggers aggregate middleware #7126 [lineus](https://github.com/lineus)
 * fix(connection): handle Model.init() when an index exists on schema + autoCreate == true #7122 [jesstelford](https://github.com/jesstelford)
 * docs(middleware): explain how to switch between document and query hooks for `remove()` #7093
 * docs(api): clean up encoding issues in SchemaType.prototype.validate docs #7091
 * docs(schema): add schema types to api docs and update links on schematypes page #7080 #7076 [lineus](https://github.com/lineus)
 * docs(model): expand model constructor docs with examples and `fields` param #7077
 * docs(aggregate): remove incorrect description of noCursorTimeout and add description of aggregate options #7056
 * docs: re-add array type to API docs #7027
 * docs(connections): add note about `members.host` errors due to bad host names in replica set #7006

5.3.2 / 2018-10-07
==================
 * fix(query): make sure to return correct result from `orFail()` #7101 #7099 [gsandorx](https://github.com/gsandorx)
 * fix(schema): handle `{ timestamps: false }` correctly #7088 #7074 [lineus](https://github.com/lineus)
 * docs: fix markdown in options.useCreateIndex documentation #7085 [Cyral](https://github.com/Cyral)
 * docs(schema): correct field name in timestamps example #7082 [kizmo04](https://github.com/kizmo04)
 * docs(migrating_to_5): correct markdown syntax #7078 [gwuah](https://github.com/gwuah)
 * fix(connection): add useFindAndModify option in connect #7059 [NormanPerrin](https://github.com/NormanPerrin)
 * fix(document): dont mark single nested path as modified if setting to the same value #7048
 * fix(populate): use WeakMap to track lean populate models rather than leanPopulateSymbol #7026
 * fix(mongoose): avoid unhandled rejection when `mongoose.connect()` errors with a callback #6997
 * fix(mongoose): isolate Schema.Types between custom Mongoose instances #6933

5.3.1 / 2018-10-02
==================
 * fix(ChangeStream): expose driver's `close()` function #7068 #7022 [lineus](https://github.com/lineus)
 * fix(model): avoid printing warning if `_id` index is set to "hashed" #7053
 * fix(populate): handle nested populate underneath lean array correctly #7052
 * fix(update): make timestamps not crash on a null or undefined update #7041
 * docs(schematypes+validation): clean up links from validation docs to schematypes docs #7040
 * fix(model): apply timestamps to nested docs in bulkWrite() #7032
 * docs(populate): rewrite refPath docs to be simpler and more direct #7013
 * docs(faq): explain why destructuring imports are not supported in FAQ #7009

5.3.0 / 2018-09-28
==================
 * feat(mongoose): support `mongoose.set('debug', WritableStream)` so you can pipe debug to stderr, file, or network #7018
 * feat(query): add useNestedStrict option #6973 #5144 [lineus](https://github.com/lineus)
 * feat(query): add getPopulatedPaths helper to Query.prototype #6970 #6677 [lineus](https://github.com/lineus)
 * feat(model): add `createCollection()` helper to make transactions easier #6948 #6711 [Fonger](https://github.com/Fonger)
 * feat(schema): add ability to do `schema.add(otherSchema)` to merge hooks, virtuals, etc. #6897
 * feat(query): add `orFail()` helper that throws an error if no documents match `filter` #6841
 * feat(mongoose): support global toObject and toJSON #6815
 * feat(connection): add deleteModel() to remove a model from a connection #6813
 * feat(mongoose): add top-level mongoose.ObjectId, mongoose.Decimal128 for easier schema declarations #6760
 * feat(aggregate+query): support for/await/of (async iterators) #6737
 * feat(mongoose): add global `now()` function that you can stub for testing timestamps #6728
 * feat(schema): support `schema.pre(RegExp, fn)` and `schema.post(RegExp, fn)` #6680
 * docs(query): add better docs for the `mongooseOptions()` function #6677
 * feat(mongoose): add support for global strict object #6858
 * feat(schema+mongoose): add autoCreate option to automatically create collections #6489
 * feat(update): update timestamps on nested subdocs when using `$set` #4412
 * feat(query+schema): add query `remove` hook and ability to switch between query `remove` and document `remove` middleware #3054

5.2.18 / 2018-09-27
===================
 * docs(migrating_to_5): add note about overwriting filter properties #7030
 * fix(query): correctly handle `select('+c')` if c is not in schema #7017
 * fix(document): check path exists before checking for required #6974
 * fix(document): retain user-defined key order on initial set with nested docs #6944
 * fix(populate): handle multiple localFields + foreignFields using `localField: function() {}` syntax #5704

5.2.17 / 2018-09-21
===================
 * docs(guide): clarify that Mongoose only increments versionKey on `save()` and add a workaround for `findOneAndUpdate()` #7038
 * fix(model): correctly handle `createIndex` option to `ensureIndexes()` #7036 #6922 [lineus](https://github.com/lineus)
 * docs(migrating_to_5): add a note about changing debug output from stderr to stdout #7034 #7018 [lineus](https://github.com/lineus)
 * fix(query): add `setUpdate()` to allow overwriting update without changing op #7024 #7012 [lineus](https://github.com/lineus)
 * fix(update): find top-level version key even if there are `$` operators in the update #7003
 * docs(model+query): explain which operators `count()` supports that `countDocuments()` doesn't #6911

5.2.16 / 2018-09-19
===================
 * fix(index): use dynamic require only when needed for better webpack support #7014 #7010 [jaydp17](https://github.com/jaydp17)
 * fix(map): handle arrays of mixed maps #6995
 * fix(populate): leave justOne as null if populating underneath a Mixed type #6985
 * fix(populate): add justOne option to allow overriding any bugs with justOne #6985
 * fix(query): add option to skip adding timestamps to an update #6980
 * docs(model+schematype): improve docs about background indexes and init() #6966
 * fix: bump mongodb -> 3.1.6 to allow connecting to srv url without credentials #6955 #6881 [lineus](https://github.com/lineus)
 * fix(connection): allow specifying `useCreateIndex` at the connection level, overrides global-level #6922
 * fix(schema): throw a helpful error if setting `ref` to an invalid value #6915

5.2.15 / 2018-09-15
===================
 * fix(populate): handle virtual justOne correctly if it isn't set #6988
 * fix(populate): consistently use lowercase `model` instead of `Model` so double-populating works with existing docs #6978
 * fix(model): allow calling `Model.init()` again after calling `dropDatabase()` #6967
 * fix(populate): find correct justOne when double-populating underneath an array #6798
 * docs(webpack): make webpack docs use es2015 preset for correct libs and use acorn to test output is valid ES5 #6740
 * fix(populate): add selectPopulatedPaths option to opt out of auto-adding `populate()`-ed fields to `select()` #6546
 * fix(model): set timestamps on bulkWrite `insertOne` and `replaceOne` #5708

5.2.14 / 2018-09-09
===================
 * docs: fix wording on promise docs to not imply queries only return promises #6983 #6982 [lineus](https://github.com/lineus)
 * fix(map): throw TypeError if keys are not string #6956
 * fix(document): ensure you can `validate()` a child doc #6931
 * fix(populate): avoid cast error if refPath points to localFields with 2 different types #6870
 * fix(populate): handle populating already-populated paths #6839
 * fix(schematype): make ObjectIds handle refPaths when checking required #6714
 * fix(model): set timestamps on bulkWrite() updates #5708

5.2.13 / 2018-09-04
===================
 * fix(map): throw TypeError if keys are not string #6968 [Fonger](https://github.com/Fonger)
 * fix(update): make array op casting work with strict:false and {} #6962 #6952 [lineus](https://github.com/lineus)
 * fix(document): add doc.deleteOne(), doc.updateOne(), doc.replaceOne() re: deprecation warnings #6959 #6940 [lineus](https://github.com/lineus)
 * docs(faq+schematypes): add note about map keys needing to be strings #6957 #6956 [lineus](https://github.com/lineus)
 * fix(schematype): remove unused if statement #6950 #6949 [cacothi](https://github.com/cacothi)
 * docs: add /docs/deprecations.html for dealing with MongoDB driver deprecation warnings #6922
 * fix(populate): handle refPath where first element in array has no refPath #6913
 * fix(mongoose): allow setting useCreateIndex option after creating a model but before initial connection succeeds #6890
 * fix(updateValidators): ensure $pull validators always get an array #6889

5.2.12 / 2018-08-30
===================
 * fix(document): disallow setting `constructor` and `prototype` if strict mode false

4.13.17 / 2018-08-30
====================
 * fix(document): disallow setting `constructor` and `prototype` if strict mode false

5.2.11 / 2018-08-30
===================
 * fix(document): disallow setting __proto__ if strict mode false
 * fix(document): run document middleware on docs embedded in maps #6945 #6938 [Fonger](https://github.com/Fonger)
 * fix(query): make castForQuery return a CastError #6943 #6927 [lineus](https://github.com/lineus)
 * fix(query): use correct `this` scope when casting query with legacy 2dsphere pairs defined in schema #6939 #6937 [Fonger](https://github.com/Fonger)
 * fix(document): avoid crash when calling `get()` on deeply nested subdocs #6929 #6925 [jakemccloskey](https://github.com/jakemccloskey)
 * fix(plugins): make saveSubdocs execute child post save hooks _after_ the actual save #6926
 * docs: add dbName to api docs for .connect() #6923 [p722](https://github.com/p722)
 * fix(populate): convert to array when schema specifies array, even if doc doesn't have an array #6908
 * fix(populate): handle `justOne` virtual populate underneath array #6867
 * fix(model): dont set versionKey on upsert if it is already `$set` #5973

4.13.16 / 2018-08-30
====================
 * fix(document): disallow setting __proto__ if strict mode false
 * feat(error): backport adding modified paths to VersionError #6928 [freewil](https://github.com/freewil)

5.2.10 / 2018-08-27
===================
 * fix: bump mongodb driver -> 3.1.4 #6920 #6903 #6884 #6799 #6741 [Fonger](https://github.com/Fonger)
 * fix(model): track `session` option for `save()` as the document's `$session()` #6909
 * fix(query): add Query.getOptions() helper #6907 [Fonger](https://github.com/Fonger)
 * fix(document): ensure array atomics get cleared after save() #6900
 * fix(aggregate): add missing redact and readConcern helpers #6895 [Fonger](https://github.com/Fonger)
 * fix: add global option `mongoose.set('useCreateIndex', true)` to avoid ensureIndex deprecation warning #6890
 * fix(query): use `projection` option to avoid deprecation warnings #6888 #6880 [Fonger](https://github.com/Fonger)
 * fix(query): use `findOneAndReplace()` internally if using `overwrite: true` with `findOneAndUpdate()` #6888 [Fonger](https://github.com/Fonger)
 * fix(document): ensure required cache gets cleared correctly between subsequent saves #6892
 * fix(aggregate): support session chaining correctly #6886 #6885 [Fonger](https://github.com/Fonger)
 * fix(query): use `projection` instead of `fields` internally for `find()` and `findOne()` to avoid deprecation warning #6880
 * fix(populate): add `getters` option to opt in to calling getters on populate #6844

5.2.9 / 2018-08-17
==================
 * fix(document): correctly propagate write concern options in save() #6877 [Fonger](https://github.com/Fonger)
 * fix: upgrade mongodb driver -> 3.1.3 for numerous fixes #6869 #6843 #6692 #6670 [simllll](https://github.com/simllll)
 * fix: correct `this` scope of default functions for DocumentArray and Array #6868 #6840 [Fonger](https://github.com/Fonger)
 * fix(types): support casting JSON form of buffers #6866 #6863 [Fonger](https://github.com/Fonger)
 * fix(query): get global runValidators option correctly #6865 #6578
 * fix(query): add Query.prototype.setQuery() analogous to `getQuery()` #6855 #6854
 * docs(connections): add note about the `family` option for IPv4 vs IPv6 and add port to example URIs #6784
 * fix(query): get global runValidators option correctly #6578

4.13.15 / 2018-08-14
====================
 * fix(mongoose): add global `usePushEach` option for easier Mongoose 4.x + MongoDB 3.6 #6858
 * chore: fix flakey tests for 4.x #6853 [Fonger](https://github.com/Fonger)
 * feat(error): add version number to VersionError #6852 [freewil](https://github.com/freewil)

5.2.8 / 2018-08-13
==================
 * docs: update `execPopulate()` code example #6851 [WJakub](https://github.com/WJakub)
 * fix(document): allow passing callback to `execPopulate()` #6851
 * fix(populate): populate with undefined fields without error #6848 #6845 [Fonger](https://github.com/Fonger)
 * docs(migrating_to_5): Add `objectIdGetter` option docs #6842 [jwalton](https://github.com/jwalton)
 * chore: run lint in parallel and only on Node.js v10 #6836 [Fonger](https://github.com/Fonger)
 * fix(populate): throw helpful error if refPath excluded in query #6834
 * docs(migrating_to_5): add note about removing runSettersOnQuery #6832
 * fix: use safe-buffer to avoid buffer deprecation errors in Node.js 10 #6829 [Fonger](https://github.com/Fonger)
 * docs(query): fix broken links #6828 [yaynick](https://github.com/yaynick)
 * docs(defaults): clarify that defaults only run on undefined #6827
 * chore: fix flakey tests #6824 [Fonger](https://github.com/Fonger)
 * docs: fix custom inspect function deprecation warning in Node.js 10 #6821 [yelworc](https://github.com/yelworc)
 * fix(document): ensure subdocs get set to init state after save() so validators can run again #6818
 * fix(query): make sure embedded query casting always throws a CastError #6803
 * fix(document): ensure `required` function only gets called once when validating #6801
 * docs(connections): note that you must specify port if using `useNewUrlParser: true` #6789
 * fix(populate): support `options.match` in virtual populate schema definition #6787
 * fix(update): strip out virtuals from updates if strict: 'throw' rather than returning an error #6731

5.2.7 / 2018-08-06
==================
 * fix(model): check `expireAfterSeconds` option when diffing indexes in syncIndexes() #6820 #6819 [christopherhex](https://github.com/christopherhex)
 * chore: fix some common test flakes in travis #6816 [Fonger](https://github.com/Fonger)
 * chore: bump eslint and webpack to avoid bad versions of eslint-scope #6814
 * test(model): add delay to session tests to improve pass rate #6811 [Fonger](https://github.com/Fonger)
 * fix(model): support options in `deleteMany` #6810 [Fonger](https://github.com/Fonger)
 * fix(query): don't use $each when pushing an array into an array #6809 [lineus](https://github.com/lineus)
 * chore: bump mquery so eslint isn't a prod dependency #6800
 * fix(populate): correctly get schema type when calling `populate()` on already populated path #6798
 * fix(populate): propagate readConcern options in populate from parent query #6792 #6785 [Fonger](https://github.com/Fonger)
 * docs(connection): add description of useNewUrlParser option #6789
 * fix(query): make select('+path') a no-op if no select prop in schema #6785
 * docs(schematype+validation): document using function syntax for custom validator message #6772
 * fix(update): throw CastError if updating with `$inc: null` #6770
 * fix(connection): throw helpful error when calling `createConnection(undefined)` #6763

5.2.6 / 2018-07-30
==================
 * fix(document): don't double-call deeply nested custom getters when using `get()` #6779 #6637
 * fix(query): upgrade mquery for readConcern() helper #6777
 * docs(schematypes): clean up typos #6773 [sajadtorkamani](https://github.com/sajadtorkamani)
 * refactor(browser): fix webpack warnings #6771 #6705
 * fix(populate): make error reported when no `localField` specified catchable #6767
 * docs(connection): use correct form in createConnection example #6766 [lineus](https://github.com/lineus)
 * fix(connection): throw helpful error when using legacy `mongoose.connect()` syntax #6756
 * fix(document): handle overwriting `$session` in `execPopulate()` #6754
 * fix(query): propagate top-level session down to `populate()` #6754
 * fix(aggregate): add `session()` helper for consistency with query api #6752
 * fix(map): avoid infinite recursion when update overwrites a map #6750
 * fix(model): be consistent about passing noop callback to mongoose.model() `init()` as well as db.model() #6707

5.2.5 / 2018-07-23
==================
 * fix(boolean): expose `convertToTrue` and `convertToFalse` for custom boolean casting #6758
 * docs(schematypes): add note about what values are converted to booleans #6758
 * fix(document): fix(document): report castError when setting single nested doc to array #6753
 * docs: prefix mongoose.Schema call with new operator #6751 [sajadtorkamani](https://github.com/sajadtorkamani)
 * docs(query): add examples and links to schema writeConcern option for writeConcern helpers #6748
 * docs(middleware): clarify that init middleware is sync #6747
 * perf(model): create error rather than modifying stack for source map perf #6735
 * fix(model): throw helpful error when passing object to aggregate() #6732
 * fix(model): pass Model instance as context to applyGetters when calling getters for virtual populate #6726 [lineus](https://github.com/lineus)
 * fix(documentarray): remove `isNew` and `save` listeners on CastError because otherwise they never get removed #6723
 * docs(model+query): clarify when to use `countDocuments()` vs `estimatedDocumentCount()` #6713
 * fix(populate): correctly set virtual nestedSchemaPath when calling populate() multiple times #6644
 * docs(connections): add note about the `family` option for IPv4 vs IPv6 and add port to example URIs #6566

5.2.4 / 2018-07-16
==================
 * docs: Model.insertMany rawResult option in api docs #6724 [lineus](https://github.com/lineus)
 * docs: fix typo on migrating to 5 guide #6722 [iagowp](https://github.com/iagowp)
 * docs: update doc about keepalive #6719 #6718 [simllll](https://github.com/simllll)
 * fix: ensure debug mode doesn't crash with sessions #6712
 * fix(document): report castError when setting single nested doc to primitive value #6710
 * fix(connection): throw helpful error if using `new db.model(foo)(bar)` #6698
 * fix(model): throw readable error with better stack trace when non-cb passed to $wrapCallback() #6640

5.2.3 / 2018-07-11
==================
 * fix(populate): if a getter is defined on the localField, use it when populating #6702 #6618 [lineus](https://github.com/lineus)
 * docs(schema): add example of nested aliases #6671
 * fix(query): add `session()` function to queries to avoid positional argument mistakes #6663
 * docs(transactions): use new session() helper to make positional args less confusing #6663
 * fix(query+model+schema): add support for `writeConcern` option and writeConcern helpers #6620
 * docs(guide): add `writeConcern` option and re-add description for `safe` option #6620
 * docs(schema): fix broken API links #6619
 * docs(connections): add information re: socketTimeoutMS and connectTimeoutMS #4789

5.2.2 / 2018-07-08
==================
 * fix(model+query): add missing estimatedDocumentCount() function #6697
 * docs(faq): improve array-defaults section #6695 [lineus](https://github.com/lineus)
 * docs(model): fix countDocuments() docs, bad copy/paste from count() docs #6694 #6643
 * fix(connection): add `startSession()` helper to connection and mongoose global #6689
 * fix: upgrade mongodb driver -> 3.1.1 for countDocuments() fix #6688 #6666
 * docs(compatibility): add MongoDB 4 range #6685
 * fix(populate): add ability to define refPath as a function #6683 [lineus](https://github.com/lineus)
 * docs: add rudimentary transactions guide #6672
 * fix(update): make setDefaultsOnInsert handle nested subdoc updates with deeply nested defaults #6665
 * docs: use latest acquit-ignore to handle examples that start with acquit:ignore:start #6657
 * fix(validation): format `properties.message` as well as `message` #6621

5.2.1 / 2018-07-03
==================
 * fix(connection): allow setting the mongodb driver's useNewUrlParser option, default to false #6656 #6648 #6647
 * fix(model): only warn on custom _id index if index only has _id key #6650

5.2.0 / 2018-07-02
==================
 * feat(model): add `countDocuments()` #6643
 * feat(model): make ensureIndexes() fail if specifying an index on _id #6605
 * feat(mongoose): add `objectIdGetter` option to remove ObjectId.prototype._id #6588
 * feat: upgrade mongodb -> 3.1.0 for full MongoDB 4.0 support #6579
 * feat(query): support `runValidators` as a global option #6578
 * perf(schema): use WeakMap instead of array for schema stack #6503
 * feat(model): decorate unique discriminator indexes with partialFilterExpressions #6347
 * feat(model): add `syncIndexes()`, drops indexes that aren't in schema #6281
 * feat(document): add default getter/setter if virtual doesn't have one #6262
 * feat(discriminator): support discriminators on nested doc arrays #6202
 * feat(update): add `Query.prototype.set()` #5770

5.1.8 / 2018-07-02
==================
 * fix: don't throw TypeError if calling save() after original save() failed with push() #6638 [evanhenke](https://github.com/evanhenke)
 * fix(query): add explain() helper and don't hydrate explain output #6625
 * docs(query): fix `setOptions()` lists #6624
 * docs: add geojson docs #6607
 * fix: bump mongodb -> 3.0.11 to avoid cyclic dependency error with retryWrites #6109

5.1.7 / 2018-06-26
==================
 * docs: add npm badge to readme #6623 [VFedyk](https://github.com/VFedyk)
 * fix(document): don't throw parallel save error if post save hooks in parallel #6614 #6611 [lineus](https://github.com/lineus)
 * fix(populate): allow dynamic ref to handle >1 model getModelsMapForPopulate #6613 #6612 [jimmytsao](https://github.com/jimmytsao)
 * fix(document): handle `push()` on triple nested document array #6602
 * docs(validation): improve update validator doc headers #6577 [joeytwiddle](https://github.com/joeytwiddle)
 * fix(document): handle document arrays in `modifiedPaths()` with includeChildren option #5904

5.1.6 / 2018-06-19
==================
 * fix: upgrade mongodb -> 3.0.10
 * docs(model+document): clarify that `save()` returns `undefined` if passed a callback #6604 [lineus](https://github.com/lineus)
 * fix(schema): apply alias when adding fields with .add() #6593
 * docs: add full list of guides and streamline nav #6592
 * docs(model): add `projection` option to `findOneAndUpdate()` #6590 [lineus](https://github.com/lineus)
 * docs: support @static JSDoc declaration #6584
 * fix(query): use boolean casting logic for $exists #6581
 * fix(query): cast all $text options to correct values #6581
 * fix(model): add support synchronous pre hooks for `createModel` #6552 [profbiss](https://github.com/profbiss)
 * docs: add note about the `applyPluginsToDiscriminators` option #4965

5.1.5 / 2018-06-11
==================
 * docs(guide): rework query helper example #6575 [lineus](https://github.com/lineus)
 * fix(populate): handle virtual populate with embedded discriminator under single nested subdoc #6571
 * docs: add string option to projections that call query select #6563 [lineus](https://github.com/lineus)
 * style: use ES6 in collection.js #6560 [l33ds](https://github.com/l33ds)
 * fix(populate): add virtual ref function ability getModelsMapForPopulate #6559 #6554 [lineus](https://github.com/lineus)
 * docs(queries): fix link #6557 [sun1x](https://github.com/sun1x)
 * fix(schema): rename indexes -> getIndexes to avoid webpack duplicate declaration #6547
 * fix(document): support `toString()` as custom method #6538
 * docs: add @instance for instance methods to be more compliant with JSDoc #6516 [treble-snake](https://github.com/treble-snake)
 * fix(populate): avoid converting to map when using mongoose-deep-populate #6460
 * docs(browser): create new browser docs page #6061

5.1.4 / 2018-06-04
==================
 * docs(faq): add hr tags for parallel save error #6550 [lineus](https://github.com/lineus)
 * docs(connection): fix broken link #6545 [iblamefish](https://github.com/iblamefish)
 * fix(populate): honor subpopulate options #6539 #6528 [lineus](https://github.com/lineus)
 * fix(populate): allow population of refpath under array #6537 #6509 [lineus](https://github.com/lineus)
 * fix(query): dont treat $set the same as the other ops in update casting #6535 [lineus](https://github.com/lineus)
 * fix: bump async -> 2.6.1 #6534 #6505 [lineus](https://github.com/lineus)
 * fix: support using a function as validation error message #6530 [lucandrade](https://github.com/lucandrade)
 * fix(populate): propagate `lean()` down to subpopulate #6498 [AbdelrahmanHafez](https://github.com/AbdelrahmanHafez)
 * docs(lambda): add info on what happens if database does down between lambda function calls #6409
 * fix(update): allow updating embedded discriminator path if discriminator key is in filter #5841

5.1.3 / 2018-05-28
==================
 * fix(document): support set() on path underneath array embedded discriminator #6526
 * chore: update lodash and nsp dev dependencies #6514 [ChristianMurphy](https://github.com/ChristianMurphy)
 * fix(document): throw readable error when saving the same doc instance more than once in parallel #6511 #6456 #4064 [lineus](https://github.com/lineus)
 * fix(populate): set correct nestedSchemaPath for virtual underneath embedded discriminator #6501 #6487 [lineus](https://github.com/lineus)
 * docs(query): add section on promises and warning about not mixing promises and callbacks #6495
 * docs(connection): add concrete example of connecting to multiple hosts #6492 [lineus](https://github.com/lineus)
 * fix(populate): handle virtual populate under single nested doc under embedded discriminator #6488
 * fix(schema): collect indexes from embedded discriminators for autoIndex build #6485
 * fix(document): handle `doc.set()` underneath embedded discriminator #6482
 * fix(document): handle set() on path under embedded discriminator with object syntax #6482
 * fix(document): handle setting nested property to object with only non-schema properties #6436

4.13.14 / 2018-05-25
====================
 * fix(model): handle retainKeyOrder option in findOneAndUpdate() #6484

5.1.2 / 2018-05-21
==================
 * docs(guide): add missing SchemaTypes #6490 [distancesprinter](https://github.com/distancesprinter)
 * fix(map): make MongooseMap.toJSON return a serialized object #6486 #6478 [lineus](https://github.com/lineus)
 * fix(query): make CustomQuery inherit from model.Query for hooks #6483 #6455 [lineus](https://github.com/lineus)
 * fix(document): prevent default falses from being skipped by $__dirty #6481 #6477 [lineus](https://github.com/lineus)
 * docs(connection): document `useDb()` #6480
 * fix(model): skip redundant clone in insertMany #6479 [d1manson](https://github.com/d1manson)
 * fix(aggregate): let replaceRoot accept objects as well as strings #6475 #6474 [lineus](https://github.com/lineus)
 * docs(model): clarify `emit()` in mapReduce and how map/reduce are run #6465
 * fix(populate): flatten array to handle multi-level nested `refPath` #6457
 * fix(date): cast small numeric strings as years #6444 [AbdelrahmanHafez](https://github.com/AbdelrahmanHafez)
 * fix(populate): remove unmatched ids when using virtual populate on already hydrated document #6435
 * fix(array): use custom array class to avoid clobbered property names #6431
 * fix(model): handle hooks for custom methods that return promises #6385

4.13.13 / 2018-05-17
====================
 * fix(update): stop clobbering $in when casting update #6441 #6339
 * fix: upgrade async -> 2.6.0 re: security warning

5.1.1 / 2018-05-14
==================
 * docs(schema): add notes in api and guide about schema.methods object #6470 #6440 [lineus](https://github.com/lineus)
 * fix(error): add modified paths to VersionError #6464 #6433 [paglias](https://github.com/paglias)
 * fix(populate): only call populate with full param signature when match is not present #6458 #6451 [lineus](https://github.com/lineus)
 * docs: fix geoNear link in migration guide #6450 [kawache](https://github.com/kawache)
 * fix(discriminator): throw readable error when `create()` with a non-existent discriminator key #6434
 * fix(populate): add `retainNullValues` option to avoid stripping out null keys #6432
 * fix(populate): handle populate in embedded discriminators underneath nested paths #6411
 * docs(model): add change streams and ToC, make terminology more consistent #5888

5.1.0 / 2018-05-10
==================
 * feat(ObjectId): add `_id` getter so you can get a usable id whether or not the path is populated #6415 #6115
 * feat(model): add Model.startSession() #6362
 * feat(document): add doc.$session() and set session on doc after query #6362
 * feat: add Map type that supports arbitrary keys #6287 #681
 * feat: add `cloneSchemas` option to mongoose global to opt in to always cloning schemas before use #6274
 * feat(model): add `findOneAndDelete()` and `findByIdAndDelete()` #6164
 * feat(document): support `$ignore()` on single nested and array subdocs #6152
 * feat(document): add warning about calling `save()` on subdocs #6152
 * fix(model): make `save()` use `updateOne()` instead of `update()` #6031
 * feat(error): add version number to VersionError #5966
 * fix(query): allow `[]` as a value for `$in` when casting #5913
 * fix(document): avoid running validators on single nested paths if only a child path is modified #5885
 * feat(schema): print warning if method conflicts with mongoose internals #5860

5.0.18 / 2018-05-09
===================
 * fix(update): stop clobbering $in when casting update #6441 #6339 [lineus](https://github.com/lineus)
 * fix: upgrade mongodb driver -> 3.0.8 to fix session issue #6437 #6357 [simllll](https://github.com/simllll)
 * fix: upgrade bson -> 1.0.5 re: https://snyk.io/vuln/npm:bson:20180225 #6423 [ChristianMurphy](https://github.com/ChristianMurphy)
 * fix: look for `valueOf()` when casting to Decimal128 #6419 #6418 [lineus](https://github.com/lineus)
 * fix: populate array of objects with space separated paths #6414 [lineus](https://github.com/lineus)
 * test: add coverage for `mongoose.pluralize()` #6412 [FastDeath](https://github.com/FastDeath)
 * fix(document): avoid running default functions on init() if path has value #6410
 * fix(document): allow saving document with `null` id #6406
 * fix: prevent casting of populated docs in document.init #6390 [lineus](https://github.com/lineus)
 * fix: remove `toHexString()` helper that was added in 5.0.15 #6359

5.0.17 / 2018-04-30
===================
 * docs(migration): certain chars in passwords may cause connection failures #6401 [markstos](https://github.com/markstos)
 * fix(document): don't throw when `push()` on a nested doc array #6398
 * fix(model): apply hooks to custom methods if specified #6385
 * fix(schema): support opting out of one timestamp field but not the other for `insertMany()` #6381
 * fix(documentarray): handle `required: true` within documentarray definition #6364
 * fix(document): ensure `isNew` is set before default functions run on init #3793

5.0.16 / 2018-04-23
===================
 * docs(api): sort api methods based on their string property #6374 [lineus](https://github.com/lineus)
 * docs(connection): fix typo in `createCollection()` #6370 [mattc41190](https://github.com/mattc41190)
 * docs(document): remove vestigial reference to `numAffected` #6367 [ekulabuhov](https://github.com/ekulabuhov)
 * docs(schema): fix typo #6366 [dhritzkiv](https://github.com/dhritzkiv)
 * docs(schematypes): add missing `minlength` and `maxlength` docs #6365 [treble-snake](https://github.com/treble-snake)
 * docs(queries): fix formatting #6360 [treble-snake](https://github.com/treble-snake)
 * docs(api): add cursors to API docs #6353 #6344 [lineus](https://github.com/lineus)
 * docs(aggregate): remove reference to non-existent `.select()` method #6346
 * fix(update): handle `required` array with update validators and $pull #6341
 * fix(update): avoid setting __v in findOneAndUpdate if it is `$set` #5973

5.0.15 / 2018-04-16
===================
 * fix: add ability for casting from number to decimal128 #6336 #6331 [lineus](https://github.com/lineus)
 * docs(middleware): enumerate the ways to error out in a hook #6315
 * fix(document): respect schema-level depopulate option for toObject() #6313
 * fix: bump mongodb driver -> 3.0.6 #6310
 * fix(number): check for `valueOf()` function to support Decimal.js #6306 #6299 [lineus](https://github.com/lineus)
 * fix(query): run array setters on query if input value is an array #6277
 * fix(versioning): don't require matching version when using array.pull() #6190
 * fix(document): add `toHexString()` function so you don't need to check whether a path is populated to get an id #6115

5.0.14 / 2018-04-09
===================
 * fix(schema): clone aliases and alternative option syntax correctly
 * fix(query): call utils.toObject in query.count like in query.find #6325 [lineus](https://github.com/lineus)
 * docs(populate): add middleware examples #6320 [BorntraegerMarc](https://github.com/BorntraegerMarc)
 * docs(compatibility): fix dead link #6319 [lacivert](https://github.com/lacivert)
 * docs(api): fix markdown parsing for parameters #6318 #6314 [lineus](https://github.com/lineus)
 * fix(populate): handle space-delimited paths in array populate #6296 #6284 [lineus](https://github.com/lineus)
 * fix(populate): support basic virtual populate underneath embedded discriminators #6273

5.0.13 / 2018-04-05
===================
 * docs(faq): add middleware to faq arrow function warning #6309 [lineus](https://github.com/lineus)
 * docs(schema): add example to loadClass() docs #6308
 * docs: clean up misc typos #6304 [sfrieson](https://github.com/sfrieson)
 * fix(document): apply virtuals when calling `toJSON()` on a nested path #6294
 * refactor(connection): use `client.db()` syntax rather than double-parsing the URI #6292 #6286
 * docs: document new behavior of required validator for arrays #6288 [daltones](https://github.com/daltones)
 * fix(schema): treat set() options as user-provided options #6274
 * fix(schema): clone discriminators correctly #6274
 * fix(update): make setDefaultsOnInsert not create subdoc if only default is id #6269
 * docs(discriminator): clarify 3rd argument to Model.discriminator() #2596

5.0.12 / 2018-03-27
===================
 * docs(query): updating model name in query API docs #6280 [lineus](https://github.com/lineus)
 * docs: fix typo in tests #6275 [styler](https://github.com/styler)
 * fix: add missing `.hint()` to aggregate #6272 #6251 [lineus](https://github.com/lineus)
 * docs(api): add headers to each API docs section for easer nav #6261
 * fix(query): ensure hooked query functions always run on next tick for chaining #6250
 * fix(populate): ensure populated array not set to null if it isn't set #6245
 * fix(connection): set readyState to disconnected if initial connection fails #6244 #6131
 * docs(model): make `create()` params show up correctly in docs #6242
 * fix(model): make error handlers work with MongoDB server errors and `insertMany()` #6228
 * fix(browser): ensure browser document builds defaults for embedded arrays correctly #6175
 * fix(timestamps): set timestamps when using `updateOne()` and `updateMany()` #6282 [gualopezb](https://github.com/gualopezb)

5.0.11 / 2018-03-19
===================
 * fix(update): handle $pull with $in in update validators #6240
 * fix(query): don't convert undefined to null when casting so driver `ignoreUndefined` option works #6236
 * docs(middleware): add example of using async/await with middleware #6235
 * fix(populate): apply justOne option before `completeMany()` so it works with lean() #6234
 * fix(query): ensure errors in user callbacks aren't caught in init #6195 #6178
 * docs(connections): document dbName option for Atlas connections #6179
 * fix(discriminator): make child schema nested paths overwrite parent schema paths #6076

4.13.12 / 2018-03-13
====================
 * fix(document): make virtual get() return undefined instead of null if no getters #6223
 * docs: fix url in useMongoClient error message #6219 #6217 [lineus](https://github.com/lineus)
 * fix(discriminator): don't copy `discriminators` property from base schema #6122 #6064

5.0.10 / 2018-03-12
===================
 * docs(schematype): add notes re: running setters on queries #6209
 * docs: fix typo #6208 [kamagatos](https://github.com/kamagatos)
 * fix(query): only call setters once on query filter props for findOneAndUpdate and findOneAndRemove #6203
 * docs: elaborate on connection string changes in migration guide #6193
 * fix(document): skip applyDefaults if subdoc is null #6187
 * docs: fix schematypes docs and link to them #6176
 * docs(faq): add FAQs re: array defaults and casting aggregation pipelines #6184 #6176 #6170 [lineus](https://github.com/lineus)
 * fix(document): ensure primitive defaults are set and built-in default functions run before setters #6155
 * fix(query): handle single embedded embedded discriminators in castForQuery #6027

5.0.9 / 2018-03-05
==================
 * perf: bump mongodb -> 3.0.4 to fix SSL perf issue #6065

5.0.8 / 2018-03-03
==================
 * docs: remove obsolete references to `emitIndexErrors` #6186 [isaackwan](https://github.com/isaackwan)
 * fix(query): don't cast findOne() until exec() so setters don't run twice #6157
 * fix: remove document_provider.web.js file #6186
 * fix(discriminator): support custom discriminator model names #6100 [wentout](https://github.com/wentout)
 * fix: support caching calls to `useDb()` #6036 [rocketspacer](https://github.com/rocketspacer)
 * fix(query): add omitUndefined option so setDefaultsOnInsert can kick in on undefined #6034
 * fix: upgrade mongodb -> 3.0.3 for reconnectTries: 0 blocking process exit fix #6028