Iterate the given data.
@param {*} data - The data to iterate.
@param {Function} callback - The process function for each element.
@returns {*} The original data.
function forEach(data, callback) {
  if (data && isFunction(callback)) {
    if (Array.isArray(data) || isNumber(data.length)
    /* array-like */
    ) {
        toArray(data).forEach(function (value, key) {
          callback.call(data, value, key, data);
        });
      } else if (isObject(data)) {
      Object.keys(data).forEach(function (key) {
        callback.call(data, data[key], key, data);
      });
    }
  }

  return data;
}