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30-seconds-of-code/snippets/debounce.md
2018-02-12 16:59:30 +10:00

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### debounce
Creates a debounced function that delays invoking the provided function until at least `ms` milliseconds have elapsed since the last time it was invoked.
Each time the debounced function is invoked, clear the current pending timeout with `clearTimeout()` and use `setTimeout()` to create a new timeout that delays invoking the function until at least `ms` milliseconds has elapsed. Use `Function.apply()` to apply the `this` context to the function and provide the necessary arguments.
Omit the second argument, `ms`, to set the timeout at a default of 0 ms.
```js
const debounce = (fn, ms = 0) => {
let timeoutId;
return function(...args) {
clearTimeout(timeoutId);
timeoutId = setTimeout(() => fn.apply(this, args), ms);
};
};
```
```js
window.addEventListener(
'resize',
debounce(() => {
console.log(window.innerWidth);
console.log(window.innerHeight);
}, 250)
); // Will log the window dimensions at most every 250ms
```