Modern JavaScript features
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This document discusses modern JavaScript features introduced in ECMAScript 2015 and later. It provides an introduction to the author and their background as a Drupal developer. It then covers JavaScript concepts like let and const variables, template literals, arrow functions, array and object destructuring, spread and rest parameters, classes, inheritance, modules, and promises. The document aims to explain these features and the differences between ECMAScript 5 and later versions of JavaScript. It concludes with a note about questions and answers.
Modern JavaScript features
- 1. axelerant.com 1 Modern JavaScript Features Kunal Kursija
- 2. axelerant.com 2 About Me... Drupal Developer @ Axelerant Twitter: @kunalkursija Drupal: https://www.drupal.org/u/kunalkursija LinkedIn: https://in.linkedin.com/in/kunalkursija
- 5. axelerant.com 5 EcmaScript Versions Version Name Year ES1 1997 ES2 1998 ES3 1999 ES5 2009 ES6 (ES2015) 2015 ES7 (ES2016) 2016 ES8 (ES2017) 2017
- 6. axelerant.com 6 Let’s check some of the Modern JavaScript features...
- 7. axelerant.com 7 let 7 ! let allows you to declare variables that are limited in scope to the block, statement, or expression on which it is used. ! x = 1 is one variable and x=2 is different variable.
- 8. axelerant.com 8 const 8 ! Just like let, const is used to declare block scoped variables. ! The const values can not change. ! Different error messages for different browsers.
- 9. axelerant.com 9 Template Literals 9 ! Template literals are strings that allows embedding of expressions into strings. ! We use back-tick(`) and not single quotes(‘) or double quotes(“). ! Multi-lines work.
- 11. axelerant.com 11 Array Destructuring Array Destructuring is a JavaScript expression that makes it possible to unpack values from arrays into distinct variables. ES5 ES6
- 12. axelerant.com 12 Object Destructuring Object Destructuring is a JavaScript expression that makes it possible to unpack values from objects into distinct variables. ES5 ES6
- 13. axelerant.com 13 Spread Operator Spread parameter can be used to expand the the values of an array. ES5 ES6
- 14. axelerant.com 14 Rest Parameter ! The Rest Parameter syntax allows us to represent an indefinite number of arguments as an array. ! Rest parameter must always be at the end. ES5 ES6
- 17. axelerant.com 17 Modules ! Exporting Modules = Making some functionality available for other modules to use. ! Importing Modules = Reusing some functionality provided by other modules. export.js import.js
- 18. axelerant.com 18 Promises The Promise is an object, Which represents the eventual completion (or failure) of an asynchronous operation, and its resulting value.
- 19. axelerant.com 19 Question & Answers