Loop over an array of json objects in JAVASCRIPT [duplicate]

Question

I'm new to Javascript, and I'm trying to loop over an array of JSON [{},{},{}, ...]

I have created this function to loop on a static Array of JSON constant, but it's not working properly even after checking online and trying.

function saveAccount() {
    const userName = document.getElementById('user_name');
    const userPassword = document.getElementById('user_password');
    const formErrorMessage = document.getElementById('fillFormError');
    
    if(userName.value == '' || userPassword.value == '')
    {
        formErrorMessage.textContent = 'Please fill the form fields first!';
        formErrorMessage.style.color = 'red';
        event.preventDefault();
    }
    else
    {
        localStorage.setItem('userName', userName.value);
        const allUsers =  '[{"username":"test3","email":"[email protected]","password":"123"},{"username":"test2","email":"[email protected]","password":"123123"},{"username":"test1","email":"[email protected]","password":"456456456"}]';//JSON.parse(localStorage.getItem('users'));
        for(var i = 0; i < allUsers.length; i++){
            var user = allUsers[i];
            console.log(user.username);
            //alert(user["username"])
            if(user.username == userName){
                console.log('USERNAME FOUND!!!!!');
            }
        }
    }
}

The purpose is to find if the username exists in my array of users. console.log(user.username); -> return undefined and the .parse also returns an error.

Why don't you parse the string? If it is parsed in your real code, try logging user and see what it gives. — Wimanicesir
– Wimanicesir, Commented May 23, 2022 at 11:13

MTN · Accepted Answer · 2022-05-23 11:07:27Z

1

allUser is currently defined as a string, which you can't loop over. Try this:

const allUsers =  [{"username":"test3","email":"[email protected]","password":"123"},{"username":"test2","email":"[email protected]","password":"123123"},{"username":"test1","email":"[email protected]","password":"456456456"}]

answered May 23, 2022 at 11:07

MTN

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Comments

Muideen Adewale · Accepted Answer · 2024-08-29 21:02:19Z

0

//Make allUsers an iterable by using JSON.parse e.g:

   var iterableAllUsers = JSON.parse(allUsers);
   for(var i = 0; i < iterableAllUsers.length; i++){
        if(iterableAllUsers[i].username == userName){
            console.log('USERNAME FOUND!!!!!');
        }
    }

answered Aug 29, 2024 at 21:02

Muideen Adewale

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