Why Does `setInterval` Only Run My Callback Once?

Why Does the setInterval Callback Execute Only Once?

Consider the following issue: you're attempting to create an infinite loop with a counter using setInterval. However, the callback function is only executing once. What could be going wrong?

The provided code is:

function timer() {
  console.log("timer!")
}

window.setInterval(timer(), 1000)

The mistake stems from using a function call instead of a function reference as the first argument of setInterval.

Correct Usage:

To fix this, you need to pass the function reference itself, like so:

function timer() {
  console.log("timer!");
}

window.setInterval(timer, 1000);

Alternatively, you can also use the following shorter syntax:

window.setInterval( function() {
  console.log("timer!");
}, 1000)

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