Babel Preset does not provide support on IE11 for Object.assign - "Object doesn't support property or method 'assign'"

Question

I am using babel-preset-env version - 1.6.1 for my react app, i am getting a error on IE :- Object doesn't support property or method 'assign'

this is my .babelrc :-

{
"presets": [
    "react",
    [
        "env",
        {
            "targets": {
                "browsers": [
                    "last 1 versions",
                    "ie >= 11"
                ]
            },
            "debug": true,
            "modules": "commonjs"
        }
    ]
],
"env": {
    "test": {
        "presets": [
            [
                "babel-preset-env",
                "react"
            ]
        ],
        "plugins": [
            "transform-object-rest-spread",
            "transform-class-properties",
            "transform-runtime",
            "babel-plugin-dynamic-import-node",
            "array-includes",
            "url-search-params-polyfill",
            "transform-object-assign"
        ]
    }
},
"plugins": [
    "transform-object-rest-spread",
    "transform-class-properties",
    "syntax-dynamic-import",
    "transform-runtime",
    "array-includes",
    "url-search-params-polyfill",
    "transform-object-assign"
]

}

i tried these polyfills :-

https://babeljs.io/docs/plugins/transform-object-assign/ https://www.npmjs.com/package/babel-plugin-object-assign

but it didn't work

i am using syntax:-

let a = Object.assign({},obj);

everywhere in my project

i need a polyfill that would work for my project.

Answer 1

You need Babel Polyfill.

Either import it in your entry JS file, or use Webpack.

import "babel-polyfill";

or in webpack.config.js

module.exports = {
  entry: ["babel-polyfill", "./app/main"]
}

NOTE : babel-polyfill Should be imported on very top else It will not work

Answer 2

Babel Polyfill is outdated as of Babel 7.4.0

(Source)

Please use core-js instead.

import "core-js/stable";
import "regenerator-runtime/runtime";

Or with Webpack:

module.exports = {
  entry: ["core-js/stable", "regenerator-runtime/runtime", "./app/main"]
}

In my case the above webpack config did not work! because I was also lacking a promise polyfill. This is the webpack.config I ended up using:

entry: { 'main': ['core-js/fn/promise', 'core-js/stable/object/assign', './wwwroot/src/app.js'] },