Package Exports

babel-plugin-transform-builtin-classes

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (babel-plugin-transform-builtin-classes) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

Babel Builtin Classes Fix

Inspired by Logan Smyth transformer, but actually very different.

This transformer aim is to fix once forever problems with native extends and Custom Elements.

// finally fixed
class List extends Array {}
console.assert(new List instanceof List);

// finally fixed too
class MyElement extends HTMLElement {
  connectedCallback() {
    this.textContent = 'hello';
  }
}

customElements.define('my-element', MyElement);

const node = new MyElement;
console.assert(node.constructor === MyElement);
console.assert(node instanceof MyElement);
console.assert(node instanceof HTMLElement);

document.body.appendChild(node);

Usage

In your Babel 6 configuration, for example in a .babelrc you might have the following, which would enable the plugin and configure it to look for any class extending Error or Array globals.

{
  "plugins": [
    // either the preset es2015 or at least the following
    "babel-plugin-transform-es2015-classes",
    ["babel-plugin-transform-builtin-classes", {
      "globals": ["Array", "Error", "HTMLElement"]
    }]
  ]
}

However, you can find all known Chrome browser classes already listed in the file lib/.babelrc too.

Compatibility

This transformer works on IE11 and every other browser with Object.setPrototypeOf or __proto__ as fallback.

There is NO IE <= 10 support. If you need IE <= 10 don't use this plugin and/or don't extend natives (recommended).