TypeError: Expected string but received a undefined

Question

在将其发布到 mongodb 数据库之前验证名称和密码时，它显示了一些错误

const Validator = require('validator');
const isEmpty = require('./is-empty');

module.exports = function validateRegisterInput(data){
    let errors = {};

    data.name = !isEmpty(data.name) ? data.name : '';
    data.email = !isEmpty(data.email) ? data.email : '';
    data.password = !isEmpty(data.password) ? data.password : '';
    data.password = !isEmpty(data.password2) ? data.password2 : '';


    if((!Validator.isLength(data.name , { min:2, max:20 }))){
        errors.name = 'Name must be between 2 and 20 characters';
    }

    if(Validator.isEmpty(data.name)){
        errors.name ='Name field is required';
    }

    if(Validator.isEmpty(data.email)){
        errors.email ='Email field is required';
    }

    if(Validator.isEmail(data.email)){
        errors.email ='Email is invalid';
    }

    if(Validator.isEmpty(data.password)){
        errors.password ='Password field is required';
    }

    if(Validator.isLength(data.password, {min:8 })){
        errors.password ='Password field is required';
    }

    if(Validator.isEmpty(data.password2)){
        errors.password2 ='Confirm Passwords field is required';
    }

    if(Validator.equals(data.password, data.password2)){
        errors.password2 = 'Passwords must match';
    }

    return {
        errors,
        isValid: isEmpty(errors)
    };
};

postman 中显示错误

TypeError: Expected string but received a undefined.
    at assertString (E:\MERN\devconnector\node_modules\validator\lib\util\assertString.js:28:11)
    at Object.isEmpty (E:\MERN\devconnector\node_modules\validator\lib\isEmpty.js:19:29)
    at validateRegisterInput (E:\MERN\devconnector\validation\register.js:38:18)
    at router.post (E:\MERN\devconnector\routes\api\users.js:27:33)
    at Layer.handle [as handle_request] (E:\MERN\devconnector\node_modules\express\lib\router\layer.js:95:5)
    at next (E:\MERN\devconnector\node_modules\express\lib\router\route.js:137:13)
    at Route.dispatch (E:\MERN\devconnector\node_modules\express\lib\router\route.js:112:3)
    at Layer.handle [as handle_request] (E:\MERN\devconnector\node_modules\express\lib\router\layer.js:95:5)
    at E:\MERN\devconnector\node_modules\express\lib\router\index.js:281:22
    at Function.process_params (E:\MERN\devconnector\node_modules\express\lib\router\index.js:335:12)
    at next (E:\MERN\devconnector\node_modules\express\lib\router\index.js:275:10)
    at Function.handle (E:\MERN\devconnector\node_modules\express\lib\router\index.js:174:3)
    at router (E:\MERN\devconnector\node_modules\express\lib\router\index.js:47:12)
    at Layer.handle [as handle_request] (E:\MERN\devconnector\node_modules\express\lib\router\layer.js:95:5)
    at trim_prefix (E:\MERN\devconnector\node_modules\express\lib\router\index.js:317:13)
    at E:\MERN\devconnector\node_modules\express\lib\router\index.js:284:7

Answer 1

请检查您在 isEmpty.js 文件中声明 isEmpty 函数的位置，您可能使用了箭头函数，这不应该。

const isEmpty = value => {
    value === undefined ||
    value === null ||
    (typeof value === "Object" && Object.keys(value).length === 0) ||
    (typeof value === "string" && value.trim().length === 0)

}

所以，把箭头函数“{}”末尾的花括号去掉，它不应该在那里。

Answer 2

尝试添加这个：

data.password**2** = !isEmpty(data.password2) ? data.password2 : '';

Answer 3

您必须添加

if("HERE"Validator.equals(data.password, data.password2)){
        errors.password2 = 'Passwords must match';
}

并在第 10

行将 "data.password" 更改为 data.password2

Answer 4

我也遇到过类似的事情。我正在验证一个名为 'name' 的密钥，但在邮递员上我发送的是 'username'.

仔细检查您在邮递员中的密钥是否与您的 data.whatever

完全匹配

Answer 5

我建议以JSON格式写入数据，然后检查content-type应该是application/json。我遇到了同样的问题，我按照我提到的方式解决了它。

Answer 6

如果您正在编写多行箭头函数，那么我们应该有明确的 return 值或结果。

  const isEmpty = value => {
  return (value === undefined ||
    value === null ||
    (typeof value === "Object" && Object.keys(value).length === 0) ||
    (typeof value === "string" && value.trim().length === 0))

};

module.exports = isEmpty;

注意：请参阅 ES6 文档以获得清晰度：http://es6-features.org/

Answer 7

看到您使用 Validator 包，我理解您想要实现的目标，因为我刚刚从我得到的这个重复 TypeErrors 中解脱出来。我也有一些拼写错误，我必须更正。所以确保你没有。

在这种情况下，我将以这种方式编写代码。它有点冗长，我会尽快重构它，我现在刚得到这个，当我看到这个问题时，我想提供我的意见。

const Validator = require("validator");
const isEmpty = require("./is-empty");
// we cant use isEmpty from validator pkg as it needs its param to be a string

// data is req.body
module.exports = function validateRegisterInput(data) {
    let errors = {};

    data.name = isEmpty(data.name) ? "" : data.name;
    data.email = isEmpty(data.email) ? "" : data.email;
    data.password = isEmpty(data.password) ? "" : data.password;
    data.password2 = isEmpty(data.password2) ? "" : data.password2;

    if (!Validator.isLength(data.name, { min: 2, max: 30 })) {
        errors.name = "Name must be between 2 and 30 characters";
    }

    if (Validator.isEmpty(data.name)) {
        errors.name = "Name field is required";
    }

    if (Validator.isEmpty(data.email)) {
        errors.email = "Email field is required";
    }

    // runs if not in email exists but not in format
    if (!Validator.isEmpty(data.email) && !Validator.isEmail(data.email)) {
        errors.email = "Email is invalid";
    }

    if (Validator.isEmpty(data.password)) {
        errors.password = "Password field is required";
    }

    // runs if password exists but not in proper format
    if (
        !Validator.isEmpty(data.password) &&
        !Validator.isLength(data.password, { min: 6, max: 30 })
    ) {
        errors.password = "Password must be at least 6 chracters";
    }

    if (Validator.isEmpty(data.password2)) {
        errors.password2 = "Password 2 is required";
    }

    // runs if not in password 2 exists but not in format
    if (
        !Validator.isEmpty(data.password2) &&
        !Validator.equals(data.password, data.password2)
    ) {
        errors.password2 = "Passwords must match";
    }

    return { errors, isValid: isEmpty(errors) };
};

Answer 8

我遇到了同样的问题，我通过在检查（isEmail、isLength、...）之前检查字段是否为（isEmpty）来修复它

例如：

if (!Validator.isLength(data.name, { min: 2, max: 30 })) {
  errors.name = "Name must be between 2 and 30 characters"
}

变成：

if (
    !Validator.isEmpty(data.name) &&
    !Validator.isLength(data.name, { min: 2, max: 30 })
) {
    errors.name = "Name must be between 2 and 30 characters";
}

TypeError: Expected string but received a undefined

TypeError: Expected string but received a undefined

validation

mongodb

reactjs

mern