How can I get returned string values in fetch()



Below code is my fetch method in my separate register.js. This is my newly created js file, so I can create my front end. At the moment I’m just trying to console.log the ending result for this fetch, but can’t get the output since I’m getting an error when I try to POST this.

error in browser console: “Uncaught (in promise) SyntaxError: Unexpected token S in JSON at position 0”

        fetch(`${rootUrl}api/users/register`,{

        method:"POST",
        headers:{
            "Content-Type": "application/json"
        },
        body:JSON.stringify({
            
                firstName: firstName,
                lastName: lastName,
                mobileNo: mobileNo,
                email: email,
                password: password
        })

    })
    .then(result=>result.json())
    .then(result =>{

        console.log(result);
    

    })

In userRouter.js, this is the route I’m fetching in register.js above:

router.post('/register', (req, res)=>{

userController.register(req.body).then(result => res.send(result))})

And the route leads to this controller in Usercontroller.js:

module.exports.register = (reqBody)=>{

//check if email already exists before registering new user
return User.find({email: reqBody.email}).then((result, error) =>{

        if(result.length != 0){

            return "EMAIL EXISTS!";

        }else{

            let newUser = new User({

                firstName: reqBody.firstName,
                lastName: reqBody.lastName,
                email:reqBody.email,
                password: bcrypt.hashSync(reqBody.password, 10),
                mobileNo: reqBody.mobileNo

            })

                return newUser.save().then((result, error)=>{

                if (error){

                    return error;

                }else{

                    return "SUCCESFULLY REGISTERED NEW USER";
                }
            })

            
        }
    })}

As you can see, this is a registration form. Everything works fine in the backend, using postman to enter values. All my condition prompts are being returned(emails exist, successful registration).

But when I tried creating a frontend for it, I can’t get my defined prompts.Like when I deliberately input a duplicate email, I can’t get the message “Email exists” that I used to get when using only postman or just backend API functionality.

I feel like something is very wrong with what I’m trying to do. I’m having trouble creating a frontend for my API which I’m not used at the moment.

Answer

You are returning a non JSON response, so you can’t use res.json(). You are simply sending a text response. So use res.text()

fetch('/your-endpoint').then((res)=>{
  return res.text();
}).then((text)=>{
 console.log(text)
})


Source: stackoverflow