Javascript Sample Programs

• Consists of javascript samples, basic to advanced concepts

Libraries to consider

• bluebird - Promisifies the calls, usage eg:

  var Promise = require('bluebird');
  var fs = Promise.promisifyAll(require('fs'));
  // Check the example in promise-sample.js

• consider pm2 module for process or cluster related solutions

• multer package for uploading files

• run babel with latest JS features using, nodemon

  // Install babel plugins
  $ npm install babel-cli babel-preset-env --save-dev
  
  // add the script to package.json
  scripts:
  {
    "babel-node": "babel-node --presets=/*a*/ --ignore='foo|bar|baz'"
  }
  
  $ nodemon --exec npm run babel-node -- path/to/script.js
  (or)
  $ nodemon --exec babel-node /path/file.js
  

• Add .babelrc file to add the @babel/preset-env with this entry

  {
      "presets": ["@babel/preset-env"]
  }

• Use esm package to use ES Modules in nodejs app in commandline node -r esm <filename.js>

• ES Modules can be used in node 13.7 (experimental feature) by specifying "type": "module" in package.json and while importing give the file with extension import {test} from './test-module.js

• Pass file name as a param to npm script as follows, Making use of esm package to compile with ESM modules given file

  scripts: {
    "start":"func() { nodemon -r esm $1; }; func",
  }

• pass the param as follows npm run start <full-path> or npm run start -- <file-name>

• To get the code coverage for all files using jest, update test script in package.json as, "jest --watchAll --coverage"