MongoDB

Install mongoose

    npm i @nestjs/mongoose mongoose

Add Module

• app.module.ts

    import { Module } from '@nestjs/common';
    import { MongooseModule } from '@nestjs/mongoose';

    @Module({
        imports: [MongooseModule.forRoot('mongodb://localhost/nest')],
    })
    export class AppModule {}

Create Schema

• schemas/cat.schema.ts

    import { Prop, Schema, SchemaFactory } from '@nestjs/mongoose';
    import { HydratedDocument } from 'mongoose';

    export type CatDocument = HydratedDocument<Cat>;

    @Schema()
    export class Cat {

        @Prop({ required: true })
        name: string;

        @Prop()
        age: number;

        @Prop()
        breed: string;

        @Prop([String])
        tags: string[];


    }

    export const CatSchema = SchemaFactory.createForClass(Cat);

Reference Collection

    @Prop({ type: mongoose.Schema.Types.ObjectId, ref: 'Owner' })
    owner: Owner;

    @Prop({ type: [{ type: mongoose.Schema.Types.ObjectId, ref: 'Owner' }] })
    owner: Owner[];

Record

    @Prop(
        raw({
            firstName: { type: String },
            lastName:  { type: String }
        })
    )
    details: Record<string, any>;

Without Decorators

    export const CatSchema = new mongoose.Schema({
        name: String,
        age: Number,
        breed: String,
    });

Include Schema in module

    @Module({
        imports: [MongooseModule.forFeature([{ name: Cat.name, schema: CatSchema }])],
        controllers: [CatsController],
        providers: [CatsService],   
    })
    export class CatsModule {}

Service

    @Injectable()
    export class CatsService {
        constructor(@InjectModel(Cat.name, 'cats') private catModel: Model<Cat>) {}
    }