nlp-toolkit/lib/idf.js

This module covers some basic nlp principles and implementations. Every implementation in this module is written as stream to only hold that data in memory that is currently processed at any step.

/**
 * Create idf.
 */


'use strict';


/**
 * MODULES.
 */
var through2 = require('through2');
var Idf = require('./components').Idf;


/**
 * FUNCTIONS.
 */
function idf(text, options) {

  if (!options && Object.prototype.toString.call(text) !== '[object Array]') {
    options = text;
    text = '';
  }

  options = options || {};

  if (text) {
    return Idf(text);
  }

  var _idf = Idf();

  return through2.obj(function (chunk, enc, callback) {

    var _chunk = (chunk.hasOwnProperty('text')) ? chunk.text : chunk;
    if (!_chunk || Object.prototype.toString.call(_chunk) !== '[object Array]' && !_chunk.hasOwnProperty('tokens')) {
      return callback(new Error('Cannot use document ' + JSON.stringify(chunk)));
    }

    _idf.add(_chunk);

    return callback();

  }, function (callback) {
    this.push(_idf);
    return callback();
  });

}


/**
 * EXPORTS.
 */
module.exports = idf;