This polyfill has been improved, better tested, and moved under the ungap umbrella.

The new version is available as @ungap/url-search-params.

This is a polyfill for the URLSearchParams API.

It is possible to simply include build/url-search-params.js or grab it via npm.

npm install url-search-params

The function is exported directly.

var URLSearchParams = require('url-search-params');

MIT Style License

In case you'd like to replace the broken global native constructor, you can check some well known issue before including this polyfill on your project/page.

<script>
try { if (new URLSearchParams('q=%2B').get('q') !== '+') throw {}; }
catch (error) {
  window.URLSearchParams = void 0;
  document.write('<script src="/js/url-search-params.js"><'+'/script>');
}
</script>

This property is already implemented in Firefox and polyfilled here only for browsers that exposes getters and setters through the HTMLAnchorElement.prototype.

In order to know if such property is supported, you must do the check as such:

if ('searchParams' in HTMLAnchorElement.prototype) {
  // polyfill for <a> links supported
}

If you do this check instead:

if (HTMLAnchorElement.prototype.searchParams) {
  // throws a TypeError
}

this polyfill will reflect native behavior, throwing a type error due access to a property in a non instance of HTMLAnchorElement.

Nothing new to learn here, just a reminder.