babel-polyfill
Babel includes a polyfill that includes a custom regenerator runtime and core-js.
This will emulate a full ES2015+ environment and is intended to be used in an application rather than a library/tool. This polyfill is automatically loaded when using babel-node
.
This means you can use new built-ins like Promise
or WeakMap
, static methods like Array.from
or Object.assign
, instance methods like Array.prototype.includes
, and generator functions (provided you use the regenerator plugin). The polyfill adds to the global scope as well as native prototypes like String
in order to do this.
Installation
npm install --save babel-polyfill
Because this is a polyfill (which will run before your source code), we need it to be a
dependency
, not adevDependency
Usage in Node / Browserify / Webpack
To include the polyfill you need to require it at the top of the entry point to your application.
Make sure it is called before all other code/require statements!
require("babel-polyfill");
If you are using ES6's import
syntax in your application's entry point, you
should instead import the polyfill at the top of the entry point to ensure the
polyfills are loaded first:
import "babel-polyfill";
With webpack.config.js
, add babel-polyfill
to your entry array:
module.exports = {
entry: ["babel-polyfill", "./app/js"]
};
Usage in Browser
Available from the dist/polyfill.js
file within a babel-polyfill
npm release.
This needs to be included before all your compiled Babel code. You can either
prepend it to your compiled code or include it in a <script>
before it.
NOTE: Do not require
this via browserify etc, use babel-polyfill
.
Details
If you are looking for something that won't modify globals to be used in a tool/library, checkout the
transform-runtime
plugin. This means you won't be able to use the instance methods mentioned above likeArray.prototype.includes
.
Note: Depending on what ES2015 methods you actually use, you may not need to use babel-polyfill
or the runtime plugin. You may want to only load the specific polyfills you are using (like Object.assign
) or just document that the environment the library is being loaded in should include certain polyfills.