linkify-it

Links recognition library with FULL unicode support. Focused on high quality link patterns detection in plain text.

Why it's awesome:

Full unicode support, with astral characters!
International domains support.
Allows rules extension & custom normalizers.

Install

npm install linkify-it --save

Browserification is also supported.

Usage examples

Example 1

var linkify = require('linkify-it')();

// Reload full tlds list & add unofficial `.onion` domain.
linkify
  .tlds(require('tlds'))          // Reload with full tlds list
  .tlds('onion', true)            // Add unofficial `.onion` domain
  .linkify.add('git:', 'http:')   // Add `git:` ptotocol as "alias"
  .linkify.add('ftp:', null)      // Disable `ftp:` ptotocol
  .set({ fuzzyIP: true });        // Enable IPs in fuzzy links (without schema)

console.log(linkify.test('Site github.com!'));  // true

console.log(linkify.match('Site github.com!')); // [ {
                                                //   schema: "",
                                                //   index: 5,
                                                //   lastIndex: 15,
                                                //   raw: "github.com",
                                                //   text: "github.com",
                                                //   url: "http://github.com",
                                                // } ]

Example 2. Add twitter mentions handler

linkify.add('@', {
  validate: function (text, pos, self) {
    var tail = text.slice(pos);

    if (!self.re.twitter) {
      self.re.twitter =  new RegExp(
        '^([a-zA-Z0-9_]){1,15}(?!_)(?=$|' + self.re.src_ZPCc + ')'
      );
    }
    if (self.re.twitter.test(tail)) {
      // Linkifier allows punctuation chars before prefix,
      // but we additionally disable `@` ("@@mention" is invalid)
      if (pos >= 2 && tail[pos - 2] === '@') {
        return false;
      }
      return tail.match(self.re.twitter)[0].length;
    }
    return 0;
  },
  normalize: function (match) {
    match.url = 'https://twitter.com/' + match.url.replace(/^@/, '');
  }
});

API

API documentation

new LinkifyIt(schemas, options)

Creates new linkifier instance with optional additional schemas. Can be called without new keyword for convenience.

By default understands:

http(s)://... , ftp://..., mailto:... & //... links
"fuzzy" links and emails (google.com, foo@bar.com).

schemas is an object, where each key/value describes protocol/rule:

key - link prefix (usually, protocol name with : at the end, skype: for example). linkify-it makes shure that prefix is not preceeded with alphanumeric char.
value - rule to check tail after link prefix
- String - just alias to existing rule
- Object
  - validate - validator function (should return matched length on success), or RegExp.
  - normalize - optional function to normalize text & url of matched result (for example, for twitter mentions).

options:

fuzzyLink - recognige URL-s without http(s):// head. Default true.
fuzzyIP - allow IPs in fuzzy links above. Can conflict with some texts like version numbers. Default false.
fuzzyEmail - recognize emails without mailto: prefix. Default true.
--- - set true to terminate link with --- (if it's considered as long dash).

.test(text)

Searches linkifiable pattern and returns true on success or false on fail.

.pretest(text)

Quick check if link MAY BE can exist. Can be used to optimize more expensive .test() calls. Return false if link can not be found, true - if .test() call needed to know exactly.

.testSchemaAt(text, name, offset)

Similar to .test() but checks only specific protocol tail exactly at given position. Returns length of found pattern (0 on fail).

.match(text)

Returns Array of found link matches or null if nothing found.

Each match has:

schema - link schema, can be empty for fuzzy links, or // for protocol-neutral links.
index - offset of matched text
lastIndex - index of next char after mathch end
raw - matched text
text - normalized text
url - link, generated from matched text

.tlds(list[, keepOld])

Load (or merge) new tlds list. Those are needed for fuzzy links (without schema) to avoid false positives. By default:

2-letter root zones are ok.
biz|com|edu|gov|net|org|pro|web|xxx|aero|asia|coop|info|museum|name|shop|рф are ok.
encoded (xn--...) root zones are ok.

If that's not enougth, you can reload defaults with more detailed zones list.

.add(schema, definition)

Add new rule with schema prefix. For definition details see constructor description. To disable existing rule use .add(name, null)

.set(options)

Override default options. Missed properties will not be changed.

License

MIT

lpinca / linkify-it