readability

# Readability.js

A standalone version of the readability library used for [Firefox Reader View](https://support.mozilla.org/kb/firefox-reader-view-clutter-free-web-pages).

## Installation

Readability is available on npm:

```bash
npm install @mozilla/readability
```

You can then `require()` it, or for web-based projects, load the `Readability.js` script from your webpage.

## Basic usage

To parse a document, you must create a new `Readability` object from a DOM document object, and then call the [`parse()`](#parse) method. Here's an example:

```javascript
var article = new Readability(document).parse();
```

If you use Readability in a web browser, you will likely be able to use a `document` reference from elsewhere (e.g. fetched via XMLHttpRequest, in a same-origin `<iframe>` you have access to, etc.). In Node.js, you can [use an external DOM library](#nodejs-usage).

## API Reference

### `new Readability(document, options)`

The `options` object accepts a number of properties, all optional:

* `debug` (boolean, default `false`): whether to enable logging.
* `maxElemsToParse` (number, default `0` i.e. no limit): the maximum number of elements to parse.
* `nbTopCandidates` (number, default `5`): the number of top candidates to consider when analysing how tight the competition is among candidates.
* `charThreshold` (number, default `500`): the number of characters an article must have in order to return a result.
* `classesToPreserve` (array): a set of classes to preserve on HTML elements when the `keepClasses` options is set to `false`.
* `keepClasses` (boolean, default `false`): whether to preserve all classes on HTML elements. When set to `false` only classes specified in the `classesToPreserve` array are kept.
* `disableJSONLD` (boolean, default `false`): when extracting page metadata, Readability gives precedence to Schema.org fields specified in the JSON-LD format. Set this option to `true` to skip JSON-LD parsing.
* `serializer` (function, default `el => el.innerHTML`) controls how the `content` property returned by the `parse()` method is produced from the root DOM element. It may be useful to specify the `serializer` as the identity function (`el => el`) to obtain a DOM element instead of a string for `content` if you plan to process it further.
* `allowedVideoRegex` (RegExp, default `undefined` ): a regular expression that matches video URLs that should be allowed to be included in the article content. If `undefined`, the [default regex](https://github.com/mozilla/readability/blob/8e8ec27cd2013940bc6f3cc609de10e35a1d9d86/Readability.js#L133) is applied.
* `linkDensityModifier` (number, default `0`): a number that is added to the base link density threshold during the shadiness checks. This can be used to penalize nodes with a high link density or vice versa.

### `parse()`

Returns an object containing the following properties:

* `title`: article title;
* `content`: HTML string of processed article content;
* `textContent`: text