Hello, Nest

Part of the TypeScript and NestJS section of Coddy's Node.js journey. Lesson 1 of 17.

In Express every route is a function you register by hand. NestJS gives each part of an API its own class, and decorators tell Nest what each class does.

@Controller('books')
export class BooksController {
    @Get()
    findAll() {
        return [{ title: 'Dune' }];
    }
}

A controller answers the requests for one path. @Controller('books') and @Get() are decorators: labels Nest reads when the app starts. Together they map findAll to GET /books, and Nest sends what the method returns as JSON with status 200. A method without a decorator is never called.

A module lists the classes that belong together. src/main.ts calls NestFactory.create(AppModule); AppModule imports TasksModule, which lists TasksController. On a laptop you would start it with npm run start; here Run does it.

Challenge

Easy

Add a method to TasksController that answers GET /tasks with the tasks array.
Press Run and send GET /tasks, then GET /task to see what a path without a route answers.

Try it yourself

import { Controller } from '@nestjs/common';

interface Task {
    id: number;
    title: string;
    done: boolean;
}

@Controller('tasks')
export class TasksController {
    private tasks: Task[] = [
        { id: 1, title: 'Write the README', done: true },
        { id: 2, title: 'Fix the login bug', done: false },
        { id: 3, title: 'Plan the sprint', done: false },
    ];

    // Add a method here that answers GET /tasks with the list.
}