Regex-trie NPM

RegexTrie

Create a regular expression to match any of the phrases added to the trie (inspired by Dan Kogai's Regexp::Trie Perl module.

Installation and Usage

Node

npm install regex-trie
require and use (see the Usage section for more comprehensive usage instructions.)

var RegexTrie = require('regex-trie'),
    trie      = new RegexTrie(),
    regex     = trie.add('foo').add('bar').toRegExp();

Browser

npm install regex-trie
create your application using RegexTrie:

// app.js
var RegexTrie = require('regex-trie'),
    trie      = new RegexTrie(),
    regex     = trie.add('foo').add('bar').toRegExp();

console.log(regex);

Use browserfy to create the the browser-safe package, e.g.: browserify app.js -o bundle.js.

Usage

var RegexTrie = require('regex-trie');

// Create a new RegexTrie instance
var trie = new RegexTrie();

// Add phrases to the trie
trie.add('foo')
    .add('bar')
    .add('baz');

// You can use an array to add phrases if you'd rather (duplicate
// pharses are ignored.)
trie.add(['foo', 'bar', 'baz']);

// Fetch a RegExp to represent all the phrases in the trie
var regex = trie.toRegExp(); // regex => /(?:foo|ba[rz])/

// What matches?
var things_to_match = ['foo', 'bar', 'baz', 'bat', 'fun', 'food'],
    match_results   = things_to_match.map(regex.test, regex);

console.log(match_results);
// => [ true, true, true, false, false, true ]

Methods

`RegexTrie()` (constructor)

Creates a new instance of RegexTrie. Currently doesn't accept any options however this will likely change as the module evolves.

`.add(phrase_to_add)`

Adds a new phrase to the trie. Accepts singleton arguments, or an array of phrases. Ignores any values which aren't literals (objects, bools, arrays, etc).

    trie.add('foo')
        .add('bar')
        .add('baz')
        .add(['who', 'what', 'when', 'where'];

All numbers (except NaN) are coerced into strings before being added.

Before adding new phrases, the trie is checked to see whether or not that phrase already exists (using contains).

`.contains(phrase)`

Will check to see if the trie contains a phrase which matches phrase, and return true or false if the phrase does or does not exist.

`.toRegExp()`

Returns a RegExp instance which should match each individual phrase in the tree. The trie will escape any character that matches: /([^A-Za-z0-9_])/. For example, if the following values are added, the pipe (OR) will be escaped:

    trie.add(['foo', '|', 'bar'].toRegExp();
    // => (?:foo|\||bar)

Regex Specific Details

The RegExp returned by regex() is a non-capturing, un-anchored regular expression meaning it'll never capture its matches and all of the following phrases will still match:

    var regex = trie.add(['foo', 'bar', 'car']).toRegExp();

    ['fool', 'afool', 'bart', 'abart', 'acar', 'acard'].forEach( function (word) {
        console.log(regex.test(word));
    });
    // Output => true, true, true, true, true, true

Development

regex-trie uses Gulp as its build system. Currently gulpfile defines a few tasks:

lint -- JSHint (see .jshintrc for this project's settings)
test -- runs mocha from gulp
docs -- yuidocjs to produce development documentation
watch -- watches for changes to JS files in ./test/ and ./lib/ and runs the lint task
default -- by default the watch task runs (which runs lint)
continuous -- runs watch (which runs lint) and test on every JS file change.

Development Dependencies

Please see package.json for the latest development dependencies. At the time of writing, you'll need:

    "mocha": "~1.17.1"
    "should": "~3.1.2"
    "gulp-jshint": "~1.4.0"
    "gulp-util": "~2.2.14"
    "gulp": "~3.5.2"
    "gulp-watch": "~0.5.0"
    "blanket": "~1.1.6"
    "gulp-yuidoc": "~0.1.0"