NextJS Decorators for API

A simple set of decorators for NextJS so you don't have to write a lot of code yourself

Decorators

List of all decorators in lib

####Main required decorators

@Req() - required, makes it clear that this is not anyhow what function

@ErrorHandler() - required, install an exception handler to your controller

####Request types

@All() - allow all types of incoming requests

@Get() - allow incoming requests with type GET only

@Post() - allow incoming requests with type POST only

@Delete() - allow incoming requests with type DELETE only

@Head() - allow incoming requests with type HEAD only

@Options() - allow incoming requests with type OPTIONS only

@Put() - allow incoming requests with type PUT only

@Patch() - allow incoming requests with type PATCH only

####Middlewares

@Middleware((req: Request, res: Response) => Promise<void> | void) - normal middleware, pass a function to it that takes two request and response parameters and returns nothing, it can be a regular function or asynchronous, you can throw exceptions in your function

@ExpressMiddleware((req: Request, res: Response, next: Function) => Promise<void> | void) - Express similar to middleware, takes in another parameter next, the function that it should perform

####Validation

Validation decorators can take two parameters, a scheme and a custom Ajv instance (optional)

@QuerySchema(schema, Ajv?)

@BodySchema(schema, Ajv?)

@ResponseSchema(schema, Ajv?)

How to use

First you need to import everything you need

Below I’ll just show what you can get from there

Errors

import {BaseError, MethodNotAllowedError, BadRequestError, ServerInternalError} from '@za-utils/next-decorators';

Types RequestError is generic type RequestError<T extents Error = Error> = BaseError & T;

import {RequestError} from '@za-utils/next-decorators';

Types Request & Response is generic type Request<T = any> = NextApiRequest & T & Response<T = any> = NextApiResponse & T;

import {Request, Response} from '@za-utils/next-decorators';

Required decorators

import {ErrorHandler, Req} from '@za-utils/next-decorators';

Method decorators

import {All, Get, Post, Delete, Head, Options, Put, Patch} from '@za-utils/next-decorators';

Middleware

import {Middleware, ExpressMiddleware} from '@za-utils/next-decorators';

Validators

import {QuerySchema, BodySchema, ResponseSchema} from '@za-utils/next-decorators';

Note that ResponseSchema, unlike QuerySchema and BodySchema, throws a Server Internal Error

Sample controller

Controller.ts

import {Req, Get, Post, Middleware, ErrorHandler, RequestError, Request, Response} from '@za-utils/next-decorators'; import {BodySchema} from "./index";

export class MyRoutesController {
    @Req()
    @Get()
    someGetRoute(req: Request, res: Response){
        console.log('no need to use req.send, req.json, req.end');

        return {
            some: 'answer'
        };
    }

    @Req()
    @Get()
    async asyncHandler(req: Request, res: Response){
        return {
            some: 'answer'
        };
    }

    @Req()
    @Get()
    @Middleware((req: Request, res: Response) => {
        if(!req.cookies)
            throw new Error('my custom error');
    })
    async middlewareHandler(req: Request, res: Response){
        console.log('this code will not start');

        return {
            some: 'answer'
        };
    }

    @Req()
    @Post()
    @BodySchema({
        type: 'object',
        properties: {
            some: {
                type: 'string'
            }   
        }
    })
    async middlewareHandler(req: Request, res: Response){
        return {
            ok: true,
            body: req.body
        };
    }

    @ErrorHandler()
    errorHandler(error: RequestError, req: Request, res: Response){
        console.log('im catch error', error);
    
        return {
            message: 'Sorry, its a error'
        };
    }
}

./pages/api/test.ts

import {MyRoutesController} from '../../Controller.ts';

const controller = new MyRoutesController();

export default controller.someGetRoute;

Ok, good

My web site: https://zaycev.dev/

(if it doesn’t work, then I haven’t finished everything yet, check back tomorrow)

Thanks for your attention

Alex Zaycev