Tic tac toe javascript. Make it so X and 0 can only be pressed once, not overwrite eachother

How can i make so that X and 0 cant overwrite and only be pressed once on every space.

const inputs = document.querySelectorAll("input")
let clicks = 1;
for (let input of inputs) {
    input.addEventListener('click', (evt) => { 
        input.value = ("0") 
        const id = evt.target.id;
        const buttonNr = id[1];
        if (clicks % 2 === 0)  {
            if(input.value = "X") 
            console.log(`Player X pressed ${buttonNr}`);
        } else {
            console.log(`Player 0 pressed ${buttonNr}`);
        } 
        clicks++ 
    })
         


        }

I tried input.value = "" return; but that did not work unless i put it at the wrong place.

>Solution :

Try this:

const inputs = document.querySelectorAll("input")
let clicks = 1;
for (let input of inputs) {
    input.addEventListener('click', (evt) => {
        // Make sure input is empty
        if(evt.target.value == "") {
            // Increment "clicks"; check if (clicks modulo 2) == 0;
            // if true place an "X" otherwise place an "O".
            evt.target.value = (clicks++ % 2 == 0) ? "X" : "O";
        }
    })
}