A request handler that uses class-transformer and class-validator to create a type-safe serverless handler

Serverless request handler is a micro-framework that's here to make your life easier. You give it an options object with what you expect the request to look like; and it does the object request transformation, request validation, response validation and error handdling.

A typical handler will look like this.

class CreateUserDto {
    @IsEmail()
    userName: string;

    @IsString()
    @MinLength(7)
    password: string;
}

class UserPathParams {
    @IsNumber()
    userId: number;
}

const options = {
    body: {
        classType: CreateUserDto
    },
    pathParameters: {
        classType: UserPathParams
    }
};


const createUser = handler(options, async (event) => {
    return Result.Ok(201, userService.create(event.pathParameters.userId, event.body));
});

1. Install module:

   npm install serverless-request-handler --save

2. reflect-metadata shim is required, install it too:

   npm install reflect-metadata --save

   and make sure to import it in a global place, like server.ts:

   import "reflect-metadata";

3. class-validator and class-transfrormer are required peer dependencies

   npm install class-validator class-transfrormer --save

4. ES6 features are used, if you are using old version of node.js you may need to install es6-shim:

   npm install es6-shim --save

   and import it in a global place like app.ts:

   import "es6-shim";