我可以验证用户输入没有后续注册吗？只有验证，没有注册

Question

如何在没有后续注册操作的情况下验证用户输入。请参阅以下示例：

    // method like this one, no subsequent signup, just validate
    Auth.verifySignupInput()
        .then(response => {
            // input is valid
        })
        .catch( err => {
            // input is invalid
            // pasword is short
            // email doesn't have @ sign
        });

// currently validation is done exactly during signUp action.
Auth.signUp( email, password )
            .then( user => {  } )
            .catch( err => { // input was invalid, short password } )