baseIsEqualDeep.js

var equalArrays = require('./equalArrays'),
    equalByTag = require('./equalByTag'),
    equalObjects = require('./equalObjects'),
    isArray = require('../lang/isArray'),
    isTypedArray = require('../lang/isTypedArray');

/** `Object#toString` result references. */
var argsTag = '[object Arguments]',
    arrayTag = '[object Array]',
    objectTag = '[object Object]';

/** Used for native method references. */
var objectProto = Object.prototype;

/** Used to check objects for own properties. */
var hasOwnProperty = objectProto.hasOwnProperty;

/**
 * Used to resolve the [`toStringTag`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-object.prototype.tostring)
 * of values.
 */
var objToString = objectProto.toString;

/**
 * A specialized version of `baseIsEqual` for arrays and objects which performs
 * deep comparisons and tracks traversed objects enabling objects with circular
 * references to be compared.
 *
 * @private
 * @param {Object} object The object to compare.
 * @param {Object} other The other object to compare.
 * @param {Function} equalFunc The function to determine equivalents of values.
 * @param {Function} [customizer] The function to customize comparing objects.
 * @param {boolean} [isLoose] Specify performing partial comparisons.
 * @param {Array} [stackA=[]] Tracks traversed `value` objects.
 * @param {Array} [stackB=[]] Tracks traversed `other` objects.
 * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
 */
function baseIsEqualDeep(object, other, equalFunc, customizer, isLoose, stackA, stackB) {
  var objIsArr = isArray(object),
      othIsArr = isArray(other),
      objTag = arrayTag,
      othTag = arrayTag;

  if (!objIsArr) {
    objTag = objToString.call(object);
    if (objTag == argsTag) {
      objTag = objectTag;
    } else if (objTag != objectTag) {
      objIsArr = isTypedArray(object);
    }
  }
  if (!othIsArr) {
    othTag = objToString.call(other);
    if (othTag == argsTag) {
      othTag = objectTag;
    } else if (othTag != objectTag) {
      othIsArr = isTypedArray(other);
    }
  }
  var objIsObj = objTag == objectTag,
      othIsObj = othTag == objectTag,
      isSameTag = objTag == othTag;

  if (isSameTag && !(objIsArr || objIsObj)) {
    return equalByTag(object, other, objTag);
  }
  if (!isLoose) {
    var objIsWrapped = objIsObj && hasOwnProperty.call(object, '__wrapped__'),
        othIsWrapped = othIsObj && hasOwnProperty.call(other, '__wrapped__');

    if (objIsWrapped || othIsWrapped) {
      return equalFunc(objIsWrapped ? object.value() : object, othIsWrapped ? other.value() : other, customizer, isLoose, stackA, stackB);
    }
  }
  if (!isSameTag) {
    return false;
  }
  // Assume cyclic values are equal.
  // For more information on detecting circular references see https://es5.github.io/#JO.
  stackA || (stackA = []);
  stackB || (stackB = []);

  var length = stackA.length;
  while (length--) {
    if (stackA[length] == object) {
      return stackB[length] == other;
    }
  }
  // Add `object` and `other` to the stack of traversed objects.
  stackA.push(object);
  stackB.push(other);

  var result = (objIsArr ? equalArrays : equalObjects)(object, other, equalFunc, customizer, isLoose, stackA, stackB);

  stackA.pop();
  stackB.pop();

  return result;
}

module.exports = baseIsEqualDeep;