Array.prototype.values() is undefined - using Babel to transpile ES6 in NodeJS environment

Question

My setup is:

$ babel --version
6.3.15 (babel-core 6.3.15)
$ node --version
v5.1.0

Using Webstorm 11 IDE in case that is important too.

I am using Babel(js) to transpile the following ES6, and have set up some logging to verify:

Array.from([ 'a', 'b' ].keys());
Array.from([ 'a', 'b' ].values());  // TypeError: ["a","b"].values is not a function
Array.from([ 'a', 'b' ].entries());

Can verify this v.quickly:

Array.prototype.values === undefined) // true

Note that keys, and entries both exist.

Any ideas what the likely cause is? (Have I missed a special options flag or something on Babel to switch on support of this feature?). Thanks for any help, and shall continue to check documentation etc in meantime.

Answer 1

Providing an answer for completeness. BabelJS requires an extra polyfill package to extend it with some extra ES6+ features - such as the one in this question.

npm install babel-polyfill --save

Then insert the following require statement towards the top of the affected module to obtain required (generator) behaviour:

require("babel-polyfill");

This should be all you need, just importing the module adds required polyfill

Answer 2

I know, you accepted the answer, but I'd highly recommend to use core-js standard library for node.js.

With this library you'll forget seeing any problems on JS features support. It includes polyfills for ECMAScript 5, ECMAScript 6: promises, symbols, collections, iterators, typed arrays, ECMAScript 7+ proposals, setImmediate, etc. Some additional features such as dictionaries or extended partial application.

It's easy to install dependency and to use it:

npm i core-js --save

Then within your project, use it this way, to include all the features it support:

// Without global namespace pollution 
var core = require('core-js/library');

Or like this, if you want to include only specific features (in your case you was missing Array.prototype.values()):

require('core-js/fn/array/values');

This lib is a "must-have" to me for every project, after I discovered it for myself. Package description can be found at official page: https://www.npmjs.com/package/core-js