Question

I have a while loop calling a function every second:

function draw (){
        console.log(then-now)
    };
var i = 0
while(i < 100){
    setTimeout(draw,1000)
    i++;
};

But this is not waiting a second between each call to draw, it is calling it 100 times at once.

Answer 1

Try setInterval:

function draw (){
    console.log(then-now)
    i++;
    if (i >= 100) clearInterval(interval);
};
var i = 0
var interval = setInterval(draw, 100);

If you wanted to use setTimeout, you’d have to set the next iteration from inside the draw function itself.

function draw (){
    console.log(then-now)
    i++;
    if (i < 100) setTimeout(draw, 100);
};
var i = 0;
setTimeout(draw, 100);

This is because setTimeout is asynchronous, so your while loop doesn’t pause — it keeps going, launching each instance of draw almost instantaneously.