@pre & @post

@pre

Typings:

interface PreHooks {
  pre<S extends object | HydratedDocument<any, any>, T = S extends Document ? S : HydratedDocument<DocumentType<S>, any>>(
    method: 'save',
    fn: PreSaveMiddlewareFunction<T>,
    options?: SchemaPreOptions
  ): ClassDecorator;
  pre<S extends object | Query<any, any>, T = S extends Query<any, any> ? S : Query<DocumentType<S>, DocumentType<S>>>(
    method: MongooseQueryMiddleware | MongooseQueryMiddleware[] | RegExp,
    fn: PreMiddlewareFunction<T>,
    options?: SchemaPreOptions
  ): ClassDecorator;
  pre<S extends object | HydratedDocument<any, any>, T = S extends Document ? S : HydratedDocument<DocumentType<S>, any>>(
    method: MongooseDocumentMiddleware | MongooseDocumentMiddleware[] | RegExp,
    fn: PreMiddlewareFunction<T>,
    options?: SchemaPreOptions
  ): ClassDecorator;
  pre<T extends Aggregate<any>>(method: 'aggregate' | RegExp, fn: PreMiddlewareFunction<T>, options?: SchemaPreOptions): ClassDecorator;
  pre<S extends AnyParamConstructor<any> | Model<any>, T = S extends Model<any> ? S : ReturnModelType<S>>(
    method: 'insertMany' | RegExp,
    fn: (this: T, next: (err?: CallbackError) => void, docs: any | Array<any>) => void | Promise<void>,
    options?: SchemaPreOptions
  ): ClassDecorator;
}

Parameters:

Name	Type	Description
method Required	string | RegExp | string[]	The Method(s) to add the fn to
fn Required	Func	The Function to run for the Method(s) set in method
options	mongoose.SchemaPreOptions	Options to set when to run the hook

@pre is used to set Document & Query pre hooks, works like schema.pre only difference is the switched options and method(fn) parameter positions.

For parameter options, look at the mongoose for schema.pre or mongoose Middleware section Naming Conflicts.

note

Arrow Functions cannot be used here, because the binding of this is required to get & modify the Document / Query / Aggregate.

Example

@pre<Car>('save', function () {
  if (this.model === 'Tesla') {
    this.isFast = true;
  }
})
class Car {
  @prop({ required: true })
  public model!: string;

  @prop()
  public isFast?: boolean;
}

@post

Typings:

interface PostHooks {
  post<S extends object | Query<any, any>, T = S extends Query<any, any> ? S : Query<DocumentType<S>, DocumentType<S>>>(
    method: MongooseQueryMiddleware | MongooseQueryMiddleware[] | RegExp,
    fn: PostMiddlewareFunction<T, QueryResultType<T>>,
    options?: SchemaPostOptions
  ): ClassDecorator;
  post<S extends object | HydratedDocument<any, any>, T = S extends Document ? S : HydratedDocument<DocumentType<S>, any>>(
    method: MongooseDocumentMiddleware | MongooseDocumentMiddleware[] | RegExp,
    fn: PostMiddlewareFunction<T, T>,
    options?: SchemaPostOptions
  ): ClassDecorator;
  post<T extends Aggregate<any>>(
    method: 'aggregate' | RegExp,
    fn: PostMiddlewareFunction<T, Array<AggregateExtract<T>>>,
    options?: SchemaPostOptions
  ): ClassDecorator;
  post<S extends AnyParamConstructor<any> | Model<any>, T = S extends Model<any> ? S : ReturnModelType<S>>(
    method: 'insertMany' | RegExp,
    fn: PostMiddlewareFunction<T, T>,
    options?: SchemaPostOptions
  ): ClassDecorator;

  // error handling post hooks
  post<S extends object | Query<any, any>, T = S extends Query<any, any> ? S : Query<DocumentType<S>, DocumentType<S>>>(
    method: MongooseQueryMiddleware | MongooseQueryMiddleware[] | RegExp,
    fn: ErrorHandlingMiddlewareFunction<T>,
    options?: SchemaPostOptions
  ): ClassDecorator;
  post<S extends object | HydratedDocument<any, any>, T = S extends Document ? S : HydratedDocument<DocumentType<S>, any>>(
    method: MongooseDocumentMiddleware | MongooseDocumentMiddleware[] | RegExp,
    fn: ErrorHandlingMiddlewareFunction<T>,
    options?: SchemaPostOptions
  ): ClassDecorator;
  post<T extends Aggregate<any>>(
    method: 'aggregate' | RegExp,
    fn: ErrorHandlingMiddlewareFunction<T, Array<any>>,
    options?: SchemaPostOptions
  ): ClassDecorator;
  post<S extends AnyParamConstructor<any> | Model<any>, T = S extends Model<any> ? S : ReturnModelType<S>>(
    method: 'insertMany' | RegExp,
    fn: ErrorHandlingMiddlewareFunction<T>,
    options?: SchemaPostOptions
  ): ClassDecorator;
}

Parameters:

Name	Type	Description
method Required	string | RegExp | string[]	The Method(s) to add the fn to
fn Required	Func	The Function to run for the Method(s) set in method
options	mongoose.SchemaPreOptions	Options to set when to run the hook

@post is used to set Document & Query pre hooks, works like schema.post only difference is the switched options and method(fn) parameter positions.

For parameter options, look at the mongoose for schema.post or mongoose Middleware section Naming Conflicts.

note

Arrow Functions cannot be used here, because the binding of this is required to get & modify the Document / Query / Aggregate.

Example

@post<Car>('save', (car) => {
  if (car.topSpeedInKmH > 300) {
    console.log(car.model, 'is fast!');
  }
})
class Car {
  @prop({ required: true })
  public model!: string;

  @prop({ required: true })
  public topSpeedInKmH!: number;
}