notes/node_modules/arr-diff/index.js

/*!
 * arr-diff <https://github.com/jonschlinkert/arr-diff>
 *
 * Copyright (c) 2014 Jon Schlinkert, contributors.
 * Licensed under the MIT License
 */

'use strict';

var flatten = require('arr-flatten');
var slice = [].slice;

/**
 * Return the difference between the first array and
 * additional arrays.
 *
 * ```js
 * var diff = require('{%= name %}');
 *
 * var a = ['a', 'b', 'c', 'd'];
 * var b = ['b', 'c'];
 *
 * console.log(diff(a, b))
 * //=> ['a', 'd']
 * ```
 *
 * @param  {Array} `a`
 * @param  {Array} `b`
 * @return {Array}
 * @api public
 */

function diff(arr, arrays) {
  var argsLen = arguments.length;
  var len = arr.length, i = -1;
  var res = [], arrays;

  if (argsLen === 1) {
    return arr;
  }

  if (argsLen > 2) {
    arrays = flatten(slice.call(arguments, 1));
  }

  while (++i < len) {
    if (!~arrays.indexOf(arr[i])) {
      res.push(arr[i]);
    }
  }
  return res;
}

/**
 * Expose `diff`
 */

module.exports = diff;