This is a lightweight(less than 10KB) polyfill lib which includes some common polyfills.

Just simply include one of the following script tags in your HTML to get the polyfills:

<!-- via jsdelivr -->
<script type="text/javascript" crossorigin="anonymous" src="https://cdn.jsdelivr.net/npm/hpolyfill@latest/dist/index.js"></script>
<!-- or via unpkg -->
<script type="text/javascript" crossorigin="anonymous" src="https://unpkg.com/hpolyfill@latest/dist/index.js"></script>

By the way, as a polyfill lib, this lib should be loaded first in most cases.

• Set
  • basic functionality
  • constructor arguments
  • convert -0 key into +0
  • set.add() returning this
  • set.forEach()
  • set.delete()
  • set.clear()
  • set.size
  • set[Symbol.iterator]()
• Map
  • basic functionality
  • constructor arguments
  • convert -0 key into +0
  • map.set() returning this
  • map.forEach()
  • map.delete()
  • map.clear()
  • map.size
  • map[Symbol.iterator]()
• Promise
  • basic functionality
  • Promise.all()
  • Promise.allSettled()
  • Promise.race()
  • Promise.resolve()
  • Promise.reject()
  • promise.finally()
• Array
  • Array.from()
  • Array.of()
  • array.includes()
  • array.fill()
  • array.find()
  • array.findIndex()
  • array.flat()
  • array.flatMap()
  • array.keys()
  • array.values()
  • array.entries()
  • array[Symbol.iterator]()
• Object
  • Object.assign()
  • Object.is()
  • Object.keys()
  • Object.values()
  • Object.entries()
  • Object.fromEntries()
• Number
  • Number.isNaN()
  • Number.isFinite()
• Math
  • Math.sign()
  • Math.trunc()
• String
  • String.raw()
  • string.includes()
  • string.repeat()
  • string.startsWith()
  • string.endsWith()
  • string.padStart()
  • string.padEnd()
  • string.trimStart()
  • string.trimEnd()
  • string[Symbol.iterator]()
• Symbol
  • basic functionality
  • Symbol.for()
  • Symbol.keyFor()
  • Symbol.iterator
  • symbol.description
• RAF
  • requestAnimationFrame()
  • cancelAnimationFrame()
• Performance
  • performance.timeOrigin
  • performance.now()
• Fetch (partial)
  • fetch()
  • Headers()
  • Request()
  • Response()

This polyfill lib only provides a partial implemention of the Fetch APIs. Since XMLHttpRequest is used internally, some features are not available.

Here are the polyfill details:

• fetch(resource, init?)
  • resource can be either an url string or an instance of Request
  • init is optional and only accepts the following options:
    • method - request method
    • credentials - no cookies if set to 'omit'; otherwise, attach cookies
    • headers - either an instance of Headers, or an array of string arrays, or a plain object representing headers
• Headers(init?)
  • full support
• Request(resource?, init?)
  • resource and init are similar to fetch()
  • request.clone(), request.json() and request.text() are supported
• Response(body?, init?)
  • body - optional response body
  • init - optional options
  • response.ok - true if the status code is between 200 and 299; false otherwise
  • response.clone(), response.json() and response.text() are supported

If you find any problem with this lib or something necessary but not included, feel free to open an issue.