验证邮箱 @param email @return

* Checks if `value` is a valid array-like length. * * **Note:** This function is based on [`ToLength`](http://ecma-international.org/ecma-262/6.0/

* Issue a request: * * Examples: * * request('GET', '/users').end(callback) * request('/users').end(callback) * request('/users',

* Checks if `value` is classified as an `arguments` object. * * @static * @memberOf _ * @category Lang * @param {*} value The value to check

判断字符创是否为空 @param str @return