function equalObjects(object, other, equalFunc, customizer, isLoose, stackA, stackB) {
  var objProps = keys(object),
      objLength = objProps.length,
      othProps = keys(other),
      othLength = othProps.length;

  if (objLength != othLength && !isLoose) {
    return false;
  }
  var index = objLength;
  while (index--) {
    var key = objProps[index];
    if (!(isLoose ? key in other : hasOwnProperty.call(other, key))) {
      return false;
    }
  }
  var skipCtor = isLoose;
  while (++index < objLength) {
    key = objProps[index];
    var objValue = object[key],
        othValue = other[key],
        result = customizer ? customizer(isLoose ? othValue : objValue, isLoose? objValue : othValue, key) : undefined;

    // Recursively compare objects (susceptible to call stack limits).
    if (!(result === undefined ? equalFunc(objValue, othValue, customizer, isLoose, stackA, stackB) : result)) {
      return false;
    }
    skipCtor || (skipCtor = key == 'constructor');
  }
  if (!skipCtor) {
    var objCtor = object.constructor,
        othCtor = other.constructor;

    // Non `Object` object instances with different constructors are not equal.
    if (objCtor != othCtor &&
        ('constructor' in object && 'constructor' in other) &&
        !(typeof objCtor == 'function' && objCtor instanceof objCtor &&
          typeof othCtor == 'function' && othCtor instanceof othCtor)) {
      return false;
    }
  }
  return true;
}
Gets the native function at `key` of `object`.

@private
@param {Object} object The object to query.
@param {string} key The key of the method to get.
@returns {*} Returns the function if it's native, else `undefined`.