Timer Functions

Timer functions run code later or again and again.

They help with delays, clocks, and repeating actions.

Think of an oven timer or a metronome.

setTimeout

This runs a function once after a wait.

The wait is measured in milliseconds.

1000 milliseconds is one second.

clearTimeout

setTimeout returns an id.

Pass that id to clearTimeout to cancel the wait.

setInterval

This runs a function again and again on a schedule.

Great for clocks and repeating game ticks.

clearInterval

Always stop intervals you no longer need with clearInterval.

Forgotten intervals keep running like a drip.

Arrow callbacks

You can pass arrow functions too.

Not exact clocks

Timers aim for the delay you ask for.

The browser may wait a little longer if it is busy.

Tip: Save the timer id. If you start an interval, plan how and when you will clear it.