Creating Tasks

Part of the TypeScript and NestJS section of Coddy's Node.js journey. Lesson 6 of 24.

A client that creates a task sends it as JSON in the request body, and needs the saved task back.

@Post()
create(@Body() review: { stars: number }) {
    this.reviews.push(review);
    return review;
}

@Post() maps POST on the controller's path to the method, and @Body() hands it the parsed JSON. Nest reads JSON bodies on its own, so there is no express.json() to add.

Nest answers a POST with 201 Created, the status that says a new resource exists, and every other method with 200. @HttpCode(200) on the method would change it; for a create, leave it.

Challenge

Easy

Clients need to add tasks, not only read them. Add a route that creates a task from the JSON the client sends.

In src/tasks/tasks.controller.ts, add a method to TasksController (call it create) for POST /tasks. Mark it with @Post(), and read the JSON body with @Body() on its parameter. Both come from @nestjs/common.
Build the new task from the body's title. Give it an id that no other task has: one more than the largest id in this.tasks. A new task is never done, so done is false.
Add the task to this.tasks, so that GET /tasks and GET /tasks/:id find it later. Return the new task.
Do not set a status yourself. Nest responds to a POST with 201 Created on its own.

Try it: choose POST, path /tasks, and the body { "title": "Buy milk" }. You get 201 and:

{ "id": 4, "title": "Buy milk", "done": false }

Send GET /tasks/4: the same task. Then POST an empty body, {}. Nothing checks the body yet, so you still get 201, with a task that has no title: { "id": 5, "done": false }. The Validation chapter fixes that.

Try it yourself

import { Controller, Get, Param, Query } 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 },
    ];

    @Get()
    findAll(@Query('done') done?: string): Task[] {
        if (done === undefined) {
            return this.tasks;
        }
        return this.tasks.filter((task) => task.done === (done === 'true'));
    }

    @Get(':id')
    findOne(@Param('id') id: string): Task | undefined {
        return this.tasks.find((task) => task.id === Number(id));
    }
}