IE11 with Promise.all()

[andersekdahl]

Running this code in the console in IE11:

Promise.all([new Promise(function (resolve) {resolve()})])

Gives me the following error:

[object Object] is not iterable!

at module.exports (https://xxx/assets/bundle.js:2904:35)
at Anonymous function (https://xxx/assets/bundle.js:2812:8)
at perform (https://xxx/assets/bundle.js:2602:6)
at all (https://xxx/assets/bundle.js:2808:6)
at eval code (eval code:1:1)
at Global code (Unknown script code:5:1)

We use Webpack and I've looked at this issue #77 but I don't think it's the same thing. We get the same error even when not using Webpacks devtool option.

I get the error when the polyfill for Promise.all calls forOf from _for-of.js with an array as the first argument and var iterFn = ITERATOR ? function(){ return iterable; } : getIterFn(iterable) returns undefined. I stepped through getIterFn (core.get-iterator-method.js) and classof(it) is Array but Iterators is an empty object which produces the error.

We import the polyfills one by one for the ones we need like this:

import 'core-js/es5';
import 'core-js/modules/es6.promise';
import 'core-js/modules/es6.array.find';
import 'core-js/modules/es6.array.find-index';
import 'core-js/modules/es7.array.includes';
import 'core-js/modules/es6.string.ends-with';
import 'core-js/modules/es6.string.starts-with';
import 'core-js/modules/es7.string.pad-end';
import 'core-js/modules/es7.string.pad-start';
import 'core-js/modules/es6.string.trim';
import 'core-js/modules/es6.string.includes';
import 'core-js/modules/es7.string.trim-left';
import 'core-js/modules/es7.string.trim-right';

Could it be that we're missing some polyfill that's required for it to work?

This seems to be a minimal reproduce test:

var forOf = require('core-js/modules/_for-of');
const x = [1, 2, 3];
forOf(x, false, (y) => {
  console.log(y);
});

The same error is thrown in IE11 but no errors in latest Firefox or Chrome.

[zloirock]

It's this case. core-js/modules path - internal API, if you not completely sure what are you doing - use core-js/fn path.

[andersekdahl]

Thanks for the fast reply, changing to the fn path solved it!