[✔️] Auto-typed-virtuals

docs/guide.md

@@ -341,6 +341,23 @@ And what if you want to do some extra processing on the name, like
 define a `fullName` property that won't get persisted to MongoDB.
 
 ```javascript
+// That can be done either by adding it to schema options:
+const personSchema = new Schema({
+  name: {
+    first: String,
+    last: String
+  }
+},{
+  virtuals:{
+    fullName:{
+      get() {
+        return this.name.first + ' ' + this.name.last;
+      }
+    }
+  }
+});
+
+// Or by using the virtual method as following:  
 personSchema.virtual('fullName').get(function() {
   return this.name.first + ' ' + this.name.last;
 });
@@ -363,6 +380,27 @@ You can also add a custom setter to your virtual that will let you set both
 first name and last name via the `fullName` virtual.
 
 ```javascript
+// Again that can be done either by adding it to schema options:
+const personSchema = new Schema({
+  name: {
+    first: String,
+    last: String
+  }
+},{
+  virtuals:{
+    fullName:{
+      get() {
+        return this.name.first + ' ' + this.name.last;
+      }
+      set(v) {
+        this.name.first = v.substr(0, v.indexOf(' '));
+        this.name.last = v.substr(v.indexOf(' ') + 1);
+      }
+    }
+  }
+});
+
+// Or by using the virtual method as following:
 personSchema.virtual('fullName').
   get(function() {
     return this.name.first + ' ' + this.name.last;

docs/typescript/virtuals.md

@@ -1,6 +1,34 @@
 # Virtuals in TypeScript
 
 [Virtuals](/docs/tutorials/virtuals.html) are computed properties: you can access virtuals on hydrated Mongoose documents, but virtuals are **not** stored in MongoDB.
+Mongoose supports auto typed virtuals so you don't need to define additional typescript interface anymore but you are still able to do so.
+
+### Automatically Inferred Types:
+
+To make mongoose able to infer virtuals type, You have to define them in schema constructor as following:
+
+```ts
+import { Schema, Model, model } from 'mongoose';
+
+const schema = new Schema(
+  {
+    firstName: String,
+    lastName: String,
+  },
+  {
+    virtuals:{
+      fullName:{
+        get(){
+          return `${this.firstName} ${this.lastName}`;
+        }
+        // virtual setter and options can be defined here as well.
+      }
+    }
+  }
+);
+```
+
+### Set virtuals type manually:
 You shouldn't define virtuals in your TypeScript [document interface](/docs/typescript.html).
 Instead, you should define a separate interface for your virtuals, and pass this interface to `Model` and `Schema`.
 

lib/schema.js

@@ -133,6 +133,24 @@ function Schema(obj, options) {
     this.add(obj);
   }
 
+  // build virtual paths
+  if (options && options.virtuals) {
+    const virtuals = options.virtuals;
+    const pathNames = Object.keys(virtuals);
+    for (const pathName of pathNames) {
+      const pathOptions = virtuals[pathName].options ? virtuals[pathName].options : undefined;
+      const virtual = this.virtual(pathName, pathOptions);
+
+      if (virtuals[pathName].get) {
+        virtual.get(virtuals[pathName].get);
+      }
+
+      if (virtuals[pathName].set) {
+        virtual.set(virtuals[pathName].set);
+      }
+    }
+  }
+
   // check if _id's value is a subdocument (gh-2276)
   const _idSubDoc = obj && obj._id && utils.isObject(obj._id);
 

test/schema.test.js

@@ -2792,4 +2792,44 @@ describe('schema', function() {
       });
     }, /Cannot use schema-level projections.*subdocument_mapping.not_selected/);
   });
+
+  it('enable defining virtual paths by using schema constructor (gh-11908)', async function() {
+    function get() {return this.email.slice(this.email.indexOf('@') + 1);}
+    function set(v) { this.email = [this.email.slice(0, this.email.indexOf('@')), v].join('@');}
+    const options = {
+      getters: true
+    };
+
+    const definition = {
+      email: { type: String }
+    };
+    const TestSchema1 = new Schema(definition);
+    TestSchema1.virtual('domain', options).set(set).get(get);
+
+    const TestSchema2 = new Schema({
+      email: { type: String }
+    }, {
+      virtuals: {
+        domain: {
+          get,
+          set,
+          options
+        }
+      }
+    });
+
+    assert.deepEqual(TestSchema2.virtuals, TestSchema1.virtuals);
+
+    const doc1 = new (mongoose.model('schema1', TestSchema1))({ email: 'test@m0_0a.com' });
+    const doc2 = new (mongoose.model('schema2', TestSchema2))({ email: 'test@m0_0a.com' });
+
+    assert.equal(doc1.domain, doc2.domain);
+
+    const mongooseDomain = 'mongoose.com';
+    doc1.domain = mongooseDomain;
+    doc2.domain = mongooseDomain;
+
+    assert.equal(doc1.domain, mongooseDomain);
+    assert.equal(doc1.domain, doc2.domain);
+  });
 });

test/types/schema.test.ts

@@ -550,7 +550,7 @@ export type AutoTypedSchemaType = {
   },
   methods: {
     instanceFn: () => 'Returned from DocumentInstanceFn'
-  },
+  }
 };
 
 // discriminator

test/types/virtuals.test.ts

@@ -1,4 +1,4 @@
-import { Document, Model, Schema, model } from 'mongoose';
+import { Document, Model, Schema, model, InferSchemaType, FlatRecord, ObtainSchemaGeneric } from 'mongoose';
 import { expectType } from 'tsd';
 
 interface IPerson {
@@ -86,3 +86,37 @@ function gh11543() {
 
   expectType<PetVirtuals>(personSchema.virtuals);
 }
+
+function autoTypedVirtuals() {
+  type AutoTypedSchemaType = InferSchemaType<typeof testSchema>;
+  type VirtualsType = { domain: string };
+  type InferredDocType = FlatRecord<AutoTypedSchemaType & ObtainSchemaGeneric<typeof testSchema, 'TVirtuals'>>;
+
+  const testSchema = new Schema({
+    email: {
+      type: String,
+      required: [true, 'email is required']
+    }
+  }, {
+    virtuals: {
+      domain: {
+        get() {
+          expectType<Document<any, any, { email: string }> & AutoTypedSchemaType>(this);
+          return this.email.slice(this.email.indexOf('@') + 1);
+        },
+        set() {
+          expectType<Document<any, any, AutoTypedSchemaType> & AutoTypedSchemaType>(this);
+        },
+        options: {}
+      }
+    }
+  });
+
+
+  const TestModel = model('AutoTypedVirtuals', testSchema);
+
+  const doc = new TestModel();
+  expectType<string>(doc.domain);
+
+  expectType<FlatRecord<AutoTypedSchemaType & VirtualsType >>({} as InferredDocType);
+}

types/index.d.ts

@@ -21,6 +21,7 @@
 /// <reference path="./utility.d.ts" />
 /// <reference path="./validation.d.ts" />
 /// <reference path="./inferschematype.d.ts" />
+/// <reference path="./virtuals.d.ts" />
 
 declare class NativeDate extends global.Date { }
 
@@ -156,15 +157,15 @@ declare module 'mongoose' {
 
   type QueryResultType<T> = T extends Query<infer ResultType, any> ? ResultType : never;
 
-  export class Schema<EnforcedDocType = any, M = Model<EnforcedDocType, any, any, any>, TInstanceMethods = {}, TQueryHelpers = {}, TVirtuals = any,
+  export class Schema<EnforcedDocType = any, M = Model<EnforcedDocType, any, any, any>, TInstanceMethods = {}, TQueryHelpers = {}, TVirtuals = {},
     TStaticMethods = {},
     TPathTypeKey extends TypeKeyBaseType = DefaultTypeKey,
     DocType extends ObtainDocumentType<DocType, EnforcedDocType, TPathTypeKey> = ObtainDocumentType<any, EnforcedDocType, TPathTypeKey>>
     extends events.EventEmitter {
     /**
      * Create a new schema
      */
-    constructor(definition?: SchemaDefinition<SchemaDefinitionType<EnforcedDocType>> | DocType, options?: SchemaOptions<TPathTypeKey, FlatRecord<DocType>, TInstanceMethods, TQueryHelpers, TStaticMethods>);
+    constructor(definition?: SchemaDefinition<SchemaDefinitionType<EnforcedDocType>> | DocType, options?: SchemaOptions<TPathTypeKey, FlatRecord<DocType>, TInstanceMethods, TQueryHelpers, TStaticMethods, TVirtuals>);
 
     /** Adds key path / schema type pairs to this schema. */
     add(obj: SchemaDefinition<SchemaDefinitionType<EnforcedDocType>> | Schema, prefix?: string): this;

types/inferschematype.d.ts

@@ -11,7 +11,8 @@ import {
   DateSchemaDefinition,
   ObtainDocumentType,
   DefaultTypeKey,
-  ObjectIdSchemaDefinition
+  ObjectIdSchemaDefinition,
+  IfEquals
 } from 'mongoose';
 
 declare module 'mongoose' {
@@ -37,7 +38,7 @@ declare module 'mongoose' {
    * // result
    * type UserType = {userName?: string}
    */
-  type InferSchemaType<SchemaType> = ObtainSchemaGeneric<SchemaType, 'DocType'> ;
+  type InferSchemaType<SchemaType> = ObtainSchemaGeneric<SchemaType, 'DocType'>;
 
   /**
    * @summary Obtains schema Generic type by using generic alias.
@@ -58,24 +59,6 @@ declare module 'mongoose' {
       }[alias]
       : unknown;
 }
-/**
- * @summary Checks if a type is "Record" or "any".
- * @description It Helps to check if user has provided schema type "EnforcedDocType"
- * @param {T} T A generic type to be checked.
- * @returns true if {@link T} is Record OR false if {@link T} is of any type.
- */
-type IsItRecordAndNotAny<T> = IfEquals<T, any, false, T extends Record<any, any> ? true : false>;
-
-/**
- * @summary Checks if two types are identical.
- * @param {T} T The first type to be compared with {@link U}.
- * @param {U} U The seconde type to be compared with {@link T}.
- * @param {Y} Y A type to be returned if {@link T} &  {@link U} are identical.
- * @param {N} N A type to be returned if {@link T} &  {@link U} are not identical.
- */
-type IfEquals<T, U, Y = true, N = false> =
-    (<G>() => G extends T ? 1 : 0) extends
-    (<G>() => G extends U ? 1 : 0) ? Y : N;
 
 /**
  * @summary Checks if a document path is required or optional.

types/models.d.ts

@@ -119,7 +119,8 @@ declare module 'mongoose' {
     AcceptsDiscriminator,
     IndexManager,
     SessionStarter {
-    new <DocType = T>(doc?: DocType, fields?: any | null, options?: boolean | AnyObject): HydratedDocument<T, TMethodsAndOverrides, TVirtuals> & ObtainSchemaGeneric<TSchema, 'TStaticMethods'>;
+    new <DocType = T>(doc?: DocType, fields?: any | null, options?: boolean | AnyObject): HydratedDocument<T, TMethodsAndOverrides,
+    IfEquals<TVirtuals, {}, ObtainSchemaGeneric<TSchema, 'TVirtuals'>, TVirtuals>> & ObtainSchemaGeneric<TSchema, 'TStaticMethods'>;
 
     aggregate<R = any>(pipeline?: PipelineStage[], options?: mongodb.AggregateOptions, callback?: Callback<R[]>): Aggregate<Array<R>>;
     aggregate<R = any>(pipeline: PipelineStage[], callback?: Callback<R[]>): Aggregate<Array<R>>;

types/schemaoptions.d.ts

@@ -10,7 +10,7 @@ declare module 'mongoose' {
   type TypeKeyBaseType = string;
 
   type DefaultTypeKey = 'type';
-  interface SchemaOptions<PathTypeKey extends TypeKeyBaseType = DefaultTypeKey, DocType = unknown, InstanceMethods = {}, QueryHelpers = {}, StaticMethods = {}, virtuals = {}> {
+  interface SchemaOptions<PathTypeKey extends TypeKeyBaseType = DefaultTypeKey, DocType = unknown, TInstanceMethods = {}, QueryHelpers = {}, TStaticMethods = {}, TVirtuals = {}> {
     /**
      * By default, Mongoose's init() function creates all the indexes defined in your model's schema by
      * calling Model.createIndexes() after you successfully connect to MongoDB. If you want to disable
@@ -191,15 +191,15 @@ declare module 'mongoose' {
     /**
      * Model Statics methods.
      */
-    statics?: Record<any, (this: Model<DocType>, ...args: any) => unknown> | StaticMethods,
+    statics?: Record<any, (this: Model<DocType>, ...args: any) => unknown> | TStaticMethods,
 
     /**
      * Document instance methods.
      */
-    methods?: Record<any, (this: HydratedDocument<DocType>, ...args: any) => unknown> | InstanceMethods,
+    methods?: Record<any, (this: HydratedDocument<DocType>, ...args: any) => unknown> | TInstanceMethods,
 
     /**
-     * Query helper functions
+     * Query helper functions.
      */
     query?: Record<any, <T extends QueryWithHelpers<unknown, DocType>>(this: T, ...args: any) => T> | QueryHelpers,
 
@@ -208,5 +208,10 @@ declare module 'mongoose' {
      * @default true
      */
     castNonArrays?: boolean;
+
+    /**
+     * Virtual paths.
+     */
+    virtuals?: SchemaOptionsVirtualsPropertyType<DocType, TVirtuals, TInstanceMethods>,
   }
 }

types/utility.d.ts

@@ -19,4 +19,23 @@ declare module 'mongoose' {
    */
    type FlatRecord<T> = { [K in keyof T]: T[K] };
 
+   /**
+ * @summary Checks if a type is "Record" or "any".
+ * @description It Helps to check if user has provided schema type "EnforcedDocType"
+ * @param {T} T A generic type to be checked.
+ * @returns true if {@link T} is Record OR false if {@link T} is of any type.
+ */
+type IsItRecordAndNotAny<T> = IfEquals<T, any, false, T extends Record<any, any> ? true : false>;
+
+/**
+ * @summary Checks if two types are identical.
+ * @param {T} T The first type to be compared with {@link U}.
+ * @param {U} U The seconde type to be compared with {@link T}.
+ * @param {Y} Y A type to be returned if {@link T} &  {@link U} are identical.
+ * @param {N} N A type to be returned if {@link T} &  {@link U} are not identical.
+ */
+type IfEquals<T, U, Y = true, N = false> =
+    (<G>() => G extends T ? 1 : 0) extends
+    (<G>() => G extends U ? 1 : 0) ? Y : N;
+
 }

types/virtuals.d.ts

@@ -0,0 +1,14 @@
+declare module 'mongoose' {
+    type VirtualPathFunctions<DocType = {}, PathValueType = unknown, TInstanceMethods = {}> = {
+      get?: TVirtualPathFN<DocType, PathValueType, TInstanceMethods, PathValueType>;
+      set?: TVirtualPathFN<DocType, PathValueType, TInstanceMethods, void>;
+      options?: VirtualTypeOptions<HydratedDocument<DocType, TInstanceMethods>, DocType>;
+    };
+
+  type TVirtualPathFN<DocType = {}, PathType = unknown, TInstanceMethods = {}, TReturn = unknown> =
+    <T = HydratedDocument<DocType, TInstanceMethods>>(this: Document<any, any, DocType> & DocType, value: PathType, virtual: VirtualType<T>, doc: Document<any, any, DocType> & DocType) => TReturn;
+
+    type SchemaOptionsVirtualsPropertyType<DocType = any, VirtualPaths = Record<any, unknown>, TInstanceMethods = {}> = {
+      [K in keyof VirtualPaths]: VirtualPathFunctions<IsItRecordAndNotAny<DocType> extends true ? DocType : any, VirtualPaths[K], TInstanceMethods>
+    };
+}