Route Parameters

Part of the TypeScript and NestJS section of Coddy's Node.js journey. Lesson 2 of 17.

A client often needs one task, not the whole list. A path can hold a parameter: a part that changes from request to request.

@Get(':isbn')
findOne(@Param('isbn') isbn: string) {
    return this.books.find((book) => book.isbn === isbn);
}

:isbn matches any value in that place of the path, so GET /books/978 reaches this method. @Param('isbn') hands that value to the method. It is always text: /books/42 gives the string '42', never the number 42.

Leave out the name and @Param() gives the object of every parameter, { isbn: '978' }, instead of the value.

Challenge

Easy

Add GET /tasks/:id: it answers the task with that id.
Send GET /tasks/2, then GET /tasks/99 and look at what an id with no task answers.

Try it yourself

import { Controller, Get } 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(): Task[] {
        return this.tasks;
    }
}