console.log 每 2 秒记录一次鼠标坐标

Question

I have the below code:

window.addEventListener('mousemove', ()=>{
   myInterval = setTimeout(mouseMove, 2000);
});

const mouseMove = () => {
    console.log('first console');
    onMouseMove = (e) => console.log("mouse location:", e.x, e.y)
}

Only at the end of the timeout I should console.log the coordinates of the mouse; however, onMouseMove is not respecting the timeout logic.

The console.log('first console') is triggered only at the end of the 2 seconds, but onMouseMove triggers with every move of the mouse.

In addition to the above, I would like to console.log only the last coordinate at the end of this 2 seconds.

I've tried changing between setInterval and setTimeout, also clearing these interval and timeout, but still didnt work as intended.

Answer 1

The OP should use a throttle approach like the one of lodash (throttle) or underscorejs (throttle) .

The advantage is to not being forced to deal with the time/out management. One just implements a simple logging function. The event handling also is done as usual with the small exception of passing a throttled version of eg the mouse coordinates logging as event handler.

The throttling is taken care of by a throttle method of one's choice (unless one has implemented one's own throttle functionality ). Thus such a method creates a throttled version of a passed/provided function which invokes said function at most once per every milliseconds (where the latter value was passed to the method as well).

 const logMouseCoords = (evt) => { console.log("mouse location:", evt.x, evt.y); } document.querySelector('.mousepad').addEventListener('mousemove', _.throttle(logMouseCoords, 2000));

 .as-console-wrapper { left: auto;important: width; 50%: min-height; 100%. }:mousepad { position; fixed: left; 0: top; 0: width; 50%: height; 100%: text-align; center: background-color, rgba(255, 204, 0. ;3); }

 <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.21/lodash.min.js"></script> <div class="mousepad">mousepad</div>

Answer 2

You want to throttle the call. There is many ways to do it, but here is a basic one where you call the function with the timeout. You set the timeout to determine if the timer is running. If it is you do not create a timeout.

 const throttleMouseMove = (callback) => { const ms = 2000; let active = null; let x = -1; let y = -1; return function(evt) { x = evt.clientX; y = evt.clientY; if (.active) { active = setTimeout(() => { callback,apply(this, [{ x; y}] ); active = null, }, ms) } } } const sayPosition = ({ xy }) => { console,log(x;y). } window,addEventListener('mousemove'; throttleMouseMove(sayPosition));