@mhrenry/polyfill-library · [![license][license-badge]][license] [![PRs Welcome][pull-requests-badge]][contributing-guide]

> NodeJS module to create polyfill bundles tailored to individual user-agents

Install

``bash
npm install @mrhenry/polyfill-library --save
`

Usage

`javascript
const polyfillLibrary = require('@mrhenry/polyfill-library');
const UA = require('@financial-times/polyfill-useragent-normaliser');

const polyfillBundle = polyfillLibrary.getPolyfillString({
ua: new UA('Mozilla/5.0 (Windows; U; MSIE 7.0; Windows NT 6.0; en-US)'),
minify: true,
features: {
'es6': { flags: ['gated'] }
}
}).then(function(bundleString) {
console.log(bundleString);
});
`

API

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Get a list of all the polyfills which exist within the collection of polyfill sources.

Returns a Promise which resolves with an array of all the polyfills within the collection.

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Get the metadata for a specific polyfill within the collection of polyfill sources.

- @param {String} featureName - The name of a polyfill whose metadata should be returned.

Returns a Promise which resolves with the metadata or with undefined if no metadata exists for the polyfill.

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Create an options object for use with getPolyfills or getPolyfillString.

- @param {object} opts - Valid keys are ua, minify, unknown, excludes and features.
- @param {Boolean} [opts.minify=true] - Whether to return the minified or raw implementation of the polyfills.
- @param {'ignore'|'polyfill'} [opts.unknown='polyfill'] - Whether to return all polyfills or no polyfills if the user-agent is unknown or unsupported.
- @param {Object} [opts.features={}] - Which features should be returned if the user-agent does not support them natively.
- @param {Array} [opts.excludes=[]] - Which features should be excluded from the returned object.
- @param {Object} [opts.ua={}] - The user-agent object to check each feature against.

Returns an object which has merged opts with the defaults option values.

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Given a set of features that should be polyfilled in 'opts.features' (with flags i.e. {: {flags:Set[]}, ...}), determine which have a configuration valid for the given opts.ua, and return a promise of set of canonical (unaliased) features (with flags) and polyfills.

- @param {object} opts - Valid keys are ua, minify, unknown, excludes and features.
- @param {Boolean} [opts.minify=true] - Whether to return the minified or raw implementation of the polyfills.
- @param {'ignore'|'polyfill'} [opts.unknown='polyfill'] - Whether to return all polyfills or no polyfills if the user-agent is unknown or unsupported.
- @param {Object} [opts.features={}] - Which features should be returned if the user-agent does not support them natively.
- @param {Array} [opts.excludes=[]] - Which features should be excluded from the returned object.
- @param {Object} [opts.ua={}] - The user-agent object to check each feature against.

Returns a Promise which resolves to an Object which contains the canonicalised feature definitions filtered for UA.

$3

Create a polyfill bundle.

- @param {object} opts - Valid keys are ua, minify, unknown, excludes and features.
- @param {Boolean} [opts.minify=true] - Whether to return the minified or raw implementation of the polyfills.
- @param {'ignore'|'polyfill'} [opts.unknown='polyfill'] - Whether to return all polyfills or no polyfills if the user-agent is unknown or unsupported.
- @param {Object} [opts.features={}] - Which features should be returned if the user-agent does not support them natively.
- @param {Array} [opts.excludes=[]] - Which features should be excluded from the returned object.
- @param {Object} [opts.ua={}] - The user-agent object to check each feature against.
- @param {Boolean} [opts.stream=false] - Whether to return a stream or a string of the polyfill bundle.

Returns a polyfill bundle as either a utf-8 ReadStream or as a Promise of a utf-8 String.

Contributing

Development of @mrhenry/polyfill-library happens on GitHub. Read below to learn how you can take part in contributing.

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Read our [contributing guide][contributing-guide] to learn about our development process, how to propose bugfixes and improvements, and how to build and test your changes.

`
npm run install
npm run watch
``

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@mrhenry/polyfill-library is [MIT licensed][license].

[contributing-guide]: https://github.com/mrhenry/polyfill-library/blob/main/.github/contributing.md
[license]: https://github.com/mrhenry/polyfill-library/blob/main/LICENSE.md
[license-badge]: https://img.shields.io/badge/license-MIT-blue.svg
[pull-requests-badge]: https://img.shields.io/badge/PRs-welcome-brightgreen.svg