If you simply replace all instances of “var” with “let” in your code, chances are it will run exactly as before. I used it all the time, and rarely ran into any issues. I never thought there was anything wrong with the “var” keyword.

You can read more about arrow functions in the Mozilla Developer Network: They are not supported in IE11 and earlier, but if you use TypeScript you can and should start using them today. Enough with those “self” and “that” variables already!Īrrow functions were added to ES6 and have become one of its most popular new features. This is shorter, and the “this” variable retains its lexical meaning as most people would expect. Now check out the same thing written using an arrow function: The “self” variable is needed to keep a reference to the current context, because “this” within the function body means something else (not very well-defined). The second advantage is the more interesting one. Arrow FunctionsĪrrow functions consist of replacing the traditional “function(parameters) ” syntax. In this blog, I want to mention two ES6 features not as well-known as classes and modules, but extremely useful and usable today: arrow functions and the let keyword.

In our company, we have been using TypeScript for a long time, which allowed us to use essential new features such as classes and modules while still targeting ECMAScript 5 so our apps run in IE 9. Unfortunately, not all are available today on all browsers, so you may have to use polyfills or tools like TypeScript or Babel if you want your apps to run in IE11 ( which still has about 12% marketshare). Some of these improvements are probably very relevant to your work, and could make your life easier and improve the quality of the code you write. With each new release, there are tons of improvements and additions to the language. We've all been following the progress of the JavaScript language, from its humble beginnings (ECMAStript 3, in 1999) to the version that is part of the HTML5 standard (ECMAScript 5, 2011), to the latest and greatest version (ECMAScript 6, aka Harmony, ES2015, ES6 Harmony) that everyone is talking about.

Es6 features