google chrome - Using ECMAScript 6

Question

I'm looking for a way to run ECMAScript 6 code in my browser's console but most browsers don't support functionality that I'm looking for. For example Firefox is the only browser that supports arrow functions.

Is there a way (extension, userscript, etc.) I can run these features on Chrome?

Answer 1

In Chrome, most of the ES6 features are hidden behind a flag called "Experimental JavaScript features". Visit chrome://flags/#enable-javascript-harmony, enable this flag, restart Chrome and you will get many new features.

Arrow functions are not yet implemented in V8/Chrome, so this flag won't "unlock" arrow functions.

Since arrow functions are a syntax change, it is not possible to support this syntax without changing the way how JavaScript is parsed. If you love developing in ES6, then you could write ES6 code and use an ES6-to-ES5 compiler to generate JavaScript code that is compatible with all existing (modern) browsers.

For example, see https://github.com/google/traceur-compiler. As of writing, it supports all of the new syntax features of ES6. Together with the flag mentioned at the top of this answer, you will get very close to the desired result.

If you want to run ES6 syntax directly from the console, then you could try to overwrite the JavaScript evaluator of the console (such that Traceur preprocesor is run before executing the code). If you fancy doing this, have a look at this answer to learn how to modify the behavior of the developer tools.