internal/equalArrays.js

define([], function() {

  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
  var undefined;

  /**
   * A specialized version of `baseIsEqualDeep` for arrays with support for
   * partial deep comparisons.
   *
   * @private
   * @param {Array} array The array to compare.
   * @param {Array} other The other array to compare.
   * @param {Function} equalFunc The function to determine equivalents of values.
   * @param {Function} [customizer] The function to customize comparing arrays.
   * @param {boolean} [isWhere] Specify performing partial comparisons.
   * @param {Array} [stackA] Tracks traversed `value` objects.
   * @param {Array} [stackB] Tracks traversed `other` objects.
   * @returns {boolean} Returns `true` if the arrays are equivalent, else `false`.
   */
  function equalArrays(array, other, equalFunc, customizer, isWhere, stackA, stackB) {
    var index = -1,
        arrLength = array.length,
        othLength = other.length,
        result = true;

    if (arrLength != othLength && !(isWhere && othLength > arrLength)) {
      return false;
    }
    // Deep compare the contents, ignoring non-numeric properties.
    while (result && ++index < arrLength) {
      var arrValue = array[index],
          othValue = other[index];

      result = undefined;
      if (customizer) {
        result = isWhere
          ? customizer(othValue, arrValue, index)
          : customizer(arrValue, othValue, index);
      }
      if (typeof result == 'undefined') {
        // Recursively compare arrays (susceptible to call stack limits).
        if (isWhere) {
          var othIndex = othLength;
          while (othIndex--) {
            othValue = other[othIndex];
            result = (arrValue && arrValue === othValue) || equalFunc(arrValue, othValue, customizer, isWhere, stackA, stackB);
            if (result) {
              break;
            }
          }
        } else {
          result = (arrValue && arrValue === othValue) || equalFunc(arrValue, othValue, customizer, isWhere, stackA, stackB);
        }
      }
    }
    return !!result;
  }

  return equalArrays;
});