Text Fragments Polyfill

This is a polyfill for the Text Fragments feature for browsers that don't support it directly.

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The implementation broadly follows the text-finding algorithms, with a few small deviations and reorganizations, and should perform similarly to renderers which have implemented this natively. It is used in Chromium for iOS as well as the Link to Text Fragment Browser Extension.

The src directory contains two files: text-fragments.js, which is the polyfilling mechanism, and text-fragment-utils.js, a module of util functions related to parsing, finding, and highlighting text fragments within the DOM.

The tools directory contains a util script used for generating a regex used in the utils module.

The test directory contains unit tests, based on Karma and Jasmine, as well as HTML files which can be loaded during those tests.

Installation

From npm:

npm install text-fragments-polyfill

From unpkg:

<script type="module>
  if (!('fragmentDirective' in Location.prototype) &&
      !('fragmentDirective' in document)) {
    import('https://unpkg.com/text-fragments-polyfill');
  }
</script>

Usage

For simple usage as a polyfill, it is sufficient to import the text-fragments.js file:

// Only load the polyfill in browsers that need it.
if (
  !('fragmentDirective' in Location.prototype) &&
  !('fragmentDirective' in document)
) {
  import('text-fragments.js');
}

Users who wish to take a more hands-on approach can reuse chunks of the logic by importing the text-fragment-utils.js module; support is provided for inclusion either as an ES6 module or using the Closure compiler.

Demo

Try the demo on a browser that does not support Text Fragments.

Development

1. Hack in /src.
2. Run npm run start and open http://localhost:8080/demo/ in a browser that does not support Text Fragments URLs directly, for example, Safari.
3. Hack, reload, hack,…
4. You can modify the Text Fragments URLs directly in /demo/index.html (look for location.hash).

License

Apache 2.0. This is not an official Google product.