How to Use `setInterval` and `clearInterval` for Controlled Function Execution?

How to Control Intervals with setInterval and clearInterval

In the context of handling keyboard events, a question arises about the appropriate use of setInterval and clearInterval for managing the execution of a function. Let's explore the differences between these methods.

setInterval: Setting Up Recurring Timers

setInterval establishes a timer that executes a function repeatedly at a specified interval in milliseconds. For example, the following code sets up a timer to call the drawAll() function every 20 milliseconds:

setInterval(drawAll, 20);

However, if you intend to call the function only once, using setInterval is not ideal, as it creates a continuous loop. To avoid this, you can utilize clearInterval.

clearInterval: Canceling Timers

clearInterval allows you to stop a recurring timer. It accepts a handle returned by setInterval as an argument. By setting the handle to 0, you can cancel the timer and prevent it from firing further:

var handle = setInterval(drawAll, 20);

// When you want to cancel it:
clearInterval(handle);
handle = 0;

Using setTimeout for One-Time Execution

If you need to schedule a function to execute only once, use setTimeout instead. It provides similar functionality but doesn't create a recurring loop. The following code calls the drawAll() function once after a 20-millisecond delay:

setTimeout(drawAll, 20);

Remember, setInterval is suitable for creating timers that repeatedly execute a function, while clearInterval is used to stop such timers. On the other hand, setTimeout is used to schedule a function to fire only once after a specified delay.

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