In other words, every time you declared a variable, whether it was declared in an if statement or a for-loop, the variable scope was set to the function-level. Until only very recently, JavaScript variable scoping could only have been bound at the function-level. Even expert developers coming from other languages have also fallen prey. New and even seasoned JavaScript developers have fallen prey to the scoping system in JavaScript. This article will introduce block-level scoping and the new let and const keywords which simplifies scoping, making code easier to understand, the new class syntax that reduces the amount of boilerplate code you have to write to create object-oriented style inheritance, and the new arrow and spread operators which reduce the amount of keystrokes developers have to do.īlock Scoping – Let’s Talk About Scoping Prior to ES2015 The new language features introduced in ES2015 improve JavaScript by making it simpler, more readable and less error-prone. I will use the term ES2015 for the rest of this article. You may have heard it called ECMAScript 6 (ES6), ECMAScript 2015(ES2015), Harmony or even JavaScript 2015. A new version of the standard has been published this summer. The ECMAScript standard has gone through several editions. This organization has the very difficult task of setting the standards for JavaScript implementations.

This article will give you a rundown of the best new features in ES2015.ĮCMAScript is the scripting language standardized by ECMA International – a standards setting body – as ECMA-262. And browser support is particularly good including most modern browsers including Microsoft Edge. These new language features reduce the amount of boilerplate code developers write, simplify JavaScript code and make developer intentions clearer.

The arrow and spread operators, the new class syntax, the let and const keywords are very visible additions to JavaScript, and their usage has spread like wildfire. Thank you for supporting the partners who make SitePoint possible. This article is part of a web development series from Microsoft.

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