Introduction to Backend development with JavaScript and TypeScript.

Table of Content

• Author
• Description
• Node Installation

---

• ES6: Basic
• ES6: Classes
• ES6: Data Manipulation
• ES6: Promise
• NodeJS: Basic
• TypeScript
• Unittests

---

• Requirements

Description

Concepts

For this project, we expect you to look at these concepts:

• JavaScript programming
• Software Linter

Resources

Read or watch:

• ECMAScript 6 - ECMAScript 2015
• Statements and declarations
• Arrow functions
• Default parameters
• Rest parameter
• Javascript ES6 — Iterables and Iterators
• Promise
• JavaScript Promise: An introduction
• Await
• Async
• Throw / Try

Learning Objectives

At the end of this project, you are expected to be able to explain to anyone, without the help of Google:

• What ES6 is
• New features introduced in ES6
• The difference between a constant and a variable
• Block-scoped variables
• Arrow functions and function parameters default to them
• Rest and spread function parameters
• String templating in ES6
• Object creation and their properties in ES6
• Iterators and for-of loops
• Promises (how, why, and what)
• How to use the then, resolve, catch methods
• How to use every method of the Promise object
• Throw / Try
• The await operator
• How to use an async function

Requirements

General

• All your files will be executed on Ubuntu 18.04 LTS using NodeJS 12.11.x
• Allowed editors: vi , vim , emacs , Visual Studio Code
• All your files should end with a new line
• A README.md file, at the root of the folder of the project, is mandatory
• Your code should use the js extension
• Your code will be tested using the Jest Testing Framework
• Your code will be analyzed using the linter ESLint along with specific rules that we’ll provide
• All of your functions must be exported

Setup

Install NodeJS 12.11.x

(in your home directory):

curl -sL https://deb.nodesource.com/setup_12.x -o nodesource_setup.sh
sudo bash nodesource_setup.sh
sudo apt install nodejs -y

$ nodejs -v
v12.11.1
$ npm -v
6.11.3

Install Jest, Babel, and ESLint

in your project directory, install Jest, Babel and ESList by using the supplied package.json and run npm install .

Configuration files

Add the files below to your project directory

package.json

{
  "scripts": {
    "lint": "./node_modules/.bin/eslint",
    "check-lint": "lint [0-9]*.js",
    "dev": "npx babel-node",
    "test": "jest",
    "full-test": "./node_modules/.bin/eslint [0-9]*.js && jest"
  },
  "devDependencies": {
    "@babel/core": "^7.6.0",
    "@babel/node": "^7.8.0",
    "@babel/preset-env": "^7.6.0",
    "eslint": "^6.4.0",
    "eslint-config-airbnb-base": "^14.0.0",
    "eslint-plugin-import": "^2.18.2",
    "eslint-plugin-jest": "^22.17.0",
    "jest": "^24.9.0"
  }
}

babel.config.js

module.exports = {
  presets: [
    [
      '@babel/preset-env',
      {
        targets: {
          node: 'current',
        },
      },
    ],
  ],
};

utils.js

Use when you get to tasks requiring uploadPhoto and createUser.

export function uploadPhoto() {
  return Promise.resolve({
    status: 200,
    body: 'photo-profile-1',
  });
}


export function createUser() {
  return Promise.resolve({
    firstName: 'Guillaume',
    lastName: 'Salva',
  });
}

.eslintrc.js

module.exports = {
  env: {
    browser: false,
    es6: true,
    jest: true,
 },
 extends: [
   'airbnb-base',
   'plugin:jest/all',
 ],
 globals: {
   Atomics: 'readonly',
   SharedArrayBuffer: 'readonly',
 },
 parserOptions: {
   ecmaVersion: 2018,
   sourceType: 'module',
 },
 plugins: ['jest'],
 rules: {
   'no-console': 'off',
   'no-shadow': 'off',
   'no-restricted-syntax': [
     'error',
     'LabeledStatement',
    'WithStatement',
   ],
 },
 overrides:[
   {
     files: ['*.js'],
     excludedFiles: 'babel.config.js',
   }
 ]
};

and…

Don’t forget to run $ npm install when you have the package.json

Response Data Format

uploadPhoto returns a response with the format

{
  status: 200,
  body: 'photo-profile-1',
}

createUser returns a response with the format

{
  firstName: 'Guillaume',
  lastName: 'Salva',
}