Building a Basic Todo List REST API in Node.js with Express

67.8K views

Open Source Your Knowledge, Become a Contributor

Technology knowledge has to be shared and made accessible for free. Join the movement.

Previous: Discover Express Next: Persistence

Parameters

Express allows to extract parameters from the url. A parameter is defined in an URL with the ":" prefix. It is aviailable as a member of request.params.

var myParam = request.params.myParam

Route parameters are named URL segments that are used to capture the values specified at their position in the URL. The captured values are populated in the req.params object, with the name of the route parameter specified in the path as their respective keys.

from http://expressjs.com/en/guide/routing.html

Exercise: Complete the PUT function

const express = require('express');
const port = 9000;
const app = express();
const bodyParser = require('body-parser');
var todos = [{id:1, title:'buy the milk'}, {id:2, title:'rent a car'}, {id:3, title:'feed the cat'}];
app.use(bodyParser.json())
app.get('/', (request, response) => response.status(200).json(todos));
app.post('/', (request, response) => {
    var newTodo = JSON.parse(request.body);
    newTodo.id = todos.length + 1;
    todos.push(newTodo);
    response.status(201).json();
});
app.put('/:id', (request, response) => {
  var id = ???TODO??? // retrieve the id parameter value
  if (todos[id - 1]){
    todos[id - 1] = request.body;
    response.status(204).send();
  }else{
    response.status(404, 'The task is not found').send();
  }
});
app.listen(port);

Last Action: DELETE

To conclude this part of the tutorial, please find bellow a basic implementation of the DELETE method.

DELETE Method

const express = require('express');
const port = 9000;
const app = express();
const bodyParser = require('./bodyparser');
var todos = [{id:1, title:'buy the milk'}, {id:2, title:'rent a car'}, {id:3, title:'feed the cat'}];
var count = todos.length;
app.use(bodyParser);
app.get('/', (request, response) => response.status(200).json(todos));
app.post('/', (request, response) => {
    var newTodo = JSON.parse(request.body);
    count = count +1;
    newTodo.id = count;
    todos.push(newTodo);
    response.status(201).json();
});
app.put('/:id', (request, response) => {
  var id = request.params.id;
  if (todos[id]){
    var updatedTodo = JSON.parse(request.body);
    todos[id] = updatedTodo;
    response.status(204).send();
  }else{
    response.status(404, 'The task is not found').send();
  }
});
app.delete('/:id', (request, response) => {
  var id = parseInt(request.params.id);
  if(todos.filter(todo => todo.id == id).length !== 0){
    todos = todos.filter(todo => todo.id !== id);
    response.status(200).send();
  }else{
    response.status(404).send();
  }
});
app.listen(port);

As you can see, all the code is in one file, we do not have a clear separation of each layer. Let's move on how the next page to add a database and also refactor and organize our code with modules.

Open Source Your Knowledge: become a Contributor and help others learn. Create New Content

Open Source Your Knowledge, Become a Contributor

3/6 Parameters

Parameters

Last Action: DELETE

Exercice Javascript

JavaScript Array Methods

Module 288 : Utilisation des techniques de programmation dans le Frontend Web

LADAPT Rhône-Métropole de Lyon - Prépa Num. - Parcours Découverte Javascript