TypeError: Expected string but received a undefined

Question

While validating the name and password before posting it to the mongodb database it is showing some errror

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)
    };
};

error showing in postman

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

Please check where you declared isEmpty function in your isEmpty.js file, you probably used an arrow function, which shouldn't be.

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

}

So, remove the curly brackets at the end of the arrow function "{}", it shouldn't be there.