require('core-js/es6/map') polyfill not working for spread Map object on IE11

Question

I use TypeScript and Babel .

I have code like:

 const map1 = new Map(...);
 const map2 = new Map(...);
 const foo = [...map1, ...map2];

If I import just:

require('core-js/es6/map');

above code (spreading) not work as expect ( IE 11 ), but if I import:

require('core-js');

code works as expect.

How to import just necessary functionality for spread Map objects?

Answer 1

我发现它需要

import 'core-js/fn/symbol/for';

Answer 2

You should give a try with babel-plugin-transform-object-rest-spread . In my case, when using babel-preset-env , object spreading was not available by default.