internal/baseIsEqualDeep.js

import Stack from './Stack';
import equalArrays from './equalArrays';
import equalByTag from './equalByTag';
import equalObjects from './equalObjects';
import getTag from './getTag';
import isArray from '../isArray';
import isHostObject from './isHostObject';
import isTypedArray from '../isTypedArray';

/** Used to compose bitmasks for comparison styles. */
var PARTIAL_COMPARE_FLAG = 2;

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

/** Used for built-in method references. */
var objectProto = Object.prototype;

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

/**
 * 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 comparisons.
 * @param {number} [bitmask] The bitmask of comparison flags. See `baseIsEqual` for more details.
 * @param {Object} [stack] Tracks traversed `object` and `other` objects.
 * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
 */
function baseIsEqualDeep(object, other, equalFunc, customizer, bitmask, stack) {
  var objIsArr = isArray(object),
      othIsArr = isArray(other),
      objTag = arrayTag,
      othTag = arrayTag;

  if (!objIsArr) {
    objTag = getTag(object);
    if (objTag == argsTag) {
      objTag = objectTag;
    } else if (objTag != objectTag) {
      objIsArr = isTypedArray(object);
    }
  }
  if (!othIsArr) {
    othTag = getTag(other);
    if (othTag == argsTag) {
      othTag = objectTag;
    } else if (othTag != objectTag) {
      othIsArr = isTypedArray(other);
    }
  }
  var objIsObj = objTag == objectTag && !isHostObject(object),
      othIsObj = othTag == objectTag && !isHostObject(other),
      isSameTag = objTag == othTag;

  if (isSameTag && !(objIsArr || objIsObj)) {
    return equalByTag(object, other, objTag, equalFunc, customizer, bitmask);
  }
  var isPartial = bitmask & PARTIAL_COMPARE_FLAG;
  if (!isPartial) {
    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, bitmask, stack);
    }
  }
  if (!isSameTag) {
    return false;
  }
  stack || (stack = new Stack);
  return (objIsArr ? equalArrays : equalObjects)(object, other, equalFunc, customizer, bitmask, stack);
}

export default baseIsEqualDeep;