@dikur/express

This package provides an adapter to generate an express router from a @dikur/http decorated class.

Generating the router

function ExpressAdapator(target: new () => any, baseRouter: Router, container?: Container, ajv?: Ajv): Router The adapter takes a class annotated by the Http decorator and returns a Express router. Parameters:

• target: a class annotated by http Decorator
• baseRouter: an express router used to attach the generated router at the class's basePath.
• container: optional parameter, a callback that takes in a class as a parameter and returns an instance of that class
  • by default it has a callback that instantiates new classes manually
  • use this to inject your DI framework of choice (e.g tsyringe: Clz => container.resolve(Clz))
• ajv: optionally pass an AJV instance
  • if you would like to extend it with formats before passing it to the adapter

@Context

Parameters decorated with the Context decorator will have express's 3 route handler parameters passed in an Object.

type Ctx = {
    req: Request,
    res: Response,
    next: NextFunction
}

Responses

Use express's response object to send responses, other functionality (setting/getting headers etc), is also done normally as with express route handlers.

class {
@Get()
    async getUsers(@Context() ctx: Ctx) {
        ctx.res.json({})
    }
}

Validation

Validation errors are raised and caught by the adapter, and passed to express's error handler using next(e), you do not need to wrap your route handlers in try catch blocks.

class DikurExpressValidationError extends Error {
    parametertype: string;
    errors: ErrorObject[]; // AJV's ErrorObject
    message: string;
    constructor(parametertype: string, errors: ErrorObject[]);
}