Question 259068 in CSS Question posted in
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Css – React for loop returns Invalid left-hand side in assignment expression

I am for looping an HTMLCollection with the goal of updating the style of every p tag. My problem is that I get Invalid left-hand side in assignment expression and I don’t know why.

var getp = document.getElementsByClassName(currentUser[0]?.username)
   for (let i of getp) {
       console.log(i?.style);
       i?.style.background = 'red'
}
Tags:

4

Answers


  1. 0

    You cannot assign a value to possibly undefined property. Instead of using optional chaining, you could use simple if condition:

    if (i) {
  i.style.background = 'red';
}
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  2. 0

    It is very simple just remove left-hend side ?

    from

    i?.style.backgroundColor = 'red'

    to

        i.style.backgroundColor = 'red'

    thanks

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  3. 0

    you can use the for loop with an Array or just a regular for loop like this

    var getp = document.getElementsByClassName(currentUser[0]?.username);
for (let i = 0; i < getp.length; i++) {
  console.log(getp[i].style);
  getp[i].style.background = 'red';
}

    tested and working perfectly

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  4. 0

    We can simple use for loop to resolve this issue

    var getp = document.getElementsByClassName(currentUser[0]?.username);
for (let i = 0; i < getp.length; i++) {
    var pElement = getp[i];
    console.log(pElement.style);
    pElement.style.background = 'red';
}

    It will work perfectly.

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