@paulcbetts/cld/index.js

Language detection for Javascript. Based on the CLD2 (Compact Language Detector) library from Google. Highly optimized for space and speed. Runs about 10x faster than other libraries. Detects over 160 languages. Full test coverage. Runs on Linux, OS X, an

var _    = require('underscore');
var cld2 = require('./build/Release/cld');

module.exports = {
  LANGUAGES          : cld2.LANGUAGES,
  DETECTED_LANGUAGES : cld2.DETECTED_LANGUAGES,
  ENCODINGS          : cld2.ENCODINGS,

  detect : function (text, options, cb) {
    if (arguments.length < 2) {
      return;
    }
    if (arguments.length < 3) {
      cb = options;
      options = {};
    }
    if (!_.isFunction(cb)) {
      return;
    }

    if (!_.isString(text) || text.length < 1) {
      return cb({message:'Empty or invalid text'});
    }

    var defaults = {
      isHTML       : false,
      languageHint : '',
      encodingHint : '',
      tldHint      : '',
      httpHint     : ''
    };
    options = _.defaults(options, defaults);

    if (!_.isBoolean(options.isHTML)) {
      return cb({message:'Invalid isHTML value'});
    }
    if (!_.isString(options.languageHint)) {
      return cb({message:'Invalid languageHint'});
    }
    if (!_.isString(options.encodingHint)) {
      return cb({message:'Invalid encodingHint'});
    }
    if (!_.isString(options.tldHint)) {
      return cb({message:'Invalid tldHint'});
    }
    if (!_.isString(options.httpHint)) {
      return cb({message:'Invalid httpHint'});
    }
    if (options.encodingHint.length > 0 &&
      !~cld2.ENCODINGS.indexOf(options.encodingHint)) {

      return cb({message:'Invalid encodingHint, see ENCODINGS'});
    }
    if (options.languageHint.length > 0 &&
      !~_.keys(cld2.LANGUAGES).indexOf(options.languageHint) &&
      !~_.values(cld2.LANGUAGES).indexOf(options.languageHint)) {

      return cb({message:'Invalid languageHint, see LANGUAGES'});
    }

    var result = cld2.detect(
      text,
      !options.isHTML,
      options.languageHint,
      options.encodingHint,
      options.tldHint,
      options.httpHint
    );

    if (result.languages.length < 1) {
      return cb({message:'Failed to identify language'});
    }

    return cb(null, result);
  }
};