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https://github.com/niksy/throttle-debounce
Throttle and debounce functions.
https://github.com/niksy/throttle-debounce
Last synced: 1 day ago
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Throttle and debounce functions.
- Host: GitHub
- URL: https://github.com/niksy/throttle-debounce
- Owner: niksy
- License: other
- Created: 2014-12-20T15:10:18.000Z (about 10 years ago)
- Default Branch: master
- Last Pushed: 2024-06-24T14:06:25.000Z (7 months ago)
- Last Synced: 2025-01-14T04:06:12.805Z (5 days ago)
- Language: JavaScript
- Homepage:
- Size: 82 KB
- Stars: 1,036
- Watchers: 5
- Forks: 106
- Open Issues: 5
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE.md
Awesome Lists containing this project
- awesome-github-star - throttle-debounce
README
# throttle-debounce
[![Build Status][ci-img]][ci]
[![BrowserStack Status][browserstack-img]][browserstack]
[![Mentioned in Awesome Micro npm Packages][awesome-img]][awesome]
Throttle and debounce functions.
This module is the same as [jquery-throttle-debounce][jquery-throttle-debounce]
([with some differences](#differences-with-original-module)), but it’s
transferred to ES Modules and CommonJS format.
## Install
```sh
npm install throttle-debounce --save
```
## Usage
### `throttle`
```js
import { throttle } from 'throttle-debounce';
const throttleFunc = throttle(
1000,
(num) => {
console.log('num:', num);
},
{ noLeading: false, noTrailing: false }
);
// Can also be used like this, because noLeading and noTrailing are false by default
const throttleFunc = throttle(1000, (num) => {
console.log('num:', num);
});
throttleFunc(1); // Will execute the callback
throttleFunc(2); // Won’t execute callback
throttleFunc(3); // Won’t execute callback
// Will execute the callback, because noTrailing is false,
// but if we set noTrailing to true, this callback won’t be executed
throttleFunc(4);
setTimeout(() => {
throttleFunc(10); // Will execute the callback
}, 1200);
// Output
// num: 1
// num: 4
// num: 10
```
### `debounce`
```js
import { debounce } from 'throttle-debounce';
const debounceFunc = debounce(
1000,
(num) => {
console.log('num:', num);
},
{ atBegin: false }
);
// Can also be used like this, because atBegin is false by default
const debounceFunc = debounce(1000, (num) => {
console.log('num:', num);
});
// Won’t execute the callback, because atBegin is false,
// but if we set atBegin to true, this callback will be executed.
debounceFunc(1);
debounceFunc(2); // Won’t execute callback
debounceFunc(3); // Won’t execute callback
// Will execute the callback,
// but if we set atBegin to true, this callback won’t be executed.
debounceFunc(4);
setTimeout(() => {
debounceFunc(10); // Will execute the callback
}, 1200);
// Output
// num: 4
// num: 10
```
### Cancelling
Debounce and throttle can both be cancelled by calling the `cancel` function.
```js
const throttleFunc = throttle(300, () => {
// Throttled function
});
throttleFunc.cancel();
const debounceFunc = debounce(300, () => {
// Debounced function
});
debounceFunc.cancel();
```
The logic that is being throttled or debounced will no longer be called.
To cancel only one upcoming debounced call, you can pass `upcomingOnly: true`
option to `cancel` function:
```js
const debounceFunc = debounce(300, () => {
// Debounced function
});
debounceFunc(); // will not be invoked
debounceFunc.cancel({ upcomingOnly: true });
debounceFunc(); // will be invoked
```
## API
### throttle(delay, callback, { noLeading, noTrailing, debounceMode })
Returns: `Function`
Throttle execution of a function. Especially useful for rate limiting execution
of handlers on events like resize and scroll.
#### delay
Type: `Number`
A zero-or-greater delay in milliseconds. For event callbacks, values around 100
or 250 (or even higher) are most useful.
#### callback
Type: `Function`
A function to be executed after delay milliseconds. The `this` context and all
arguments are passed through, as-is, to `callback` when the throttled-function
is executed.
#### noTrailing
Type: `Boolean`
Optional, defaults to false. If noTrailing is true, callback will only execute
every `delay` milliseconds while the throttled-function is being called. If
noTrailing is false or unspecified, callback will be executed one final time
after the last throttled-function call. (After the throttled-function has not
been called for `delay` milliseconds, the internal counter is reset)
#### noLeading
Type: `Boolean`
Optional, defaults to false. If noLeading is false, the first throttled-function
call will execute callback immediately. If noLeading is true, the first the
callback execution will be skipped. It should be noted that callback will never
executed if both noLeading = true and noTrailing = true.
#### debounceMode
Type: `Boolean`
If `debounceMode` is true (at begin), schedule `clear` to execute after `delay`
ms. If `debounceMode` is false (at end), schedule `callback` to execute after
`delay` ms.
### debounce(delay, callback, { atBegin })
Returns: `Function`
Debounce execution of a function. Debouncing, unlike throttling, guarantees that
a function is only executed a single time, either at the very beginning of a
series of calls, or at the very end.
#### delay
Type: `Number`
A zero-or-greater delay in milliseconds. For event callbacks, values around 100
or 250 (or even higher) are most useful.
#### callback
Type: `Function`
A function to be executed after delay milliseconds. The `this` context and all
arguments are passed through, as-is, to `callback` when the debounced-function
is executed.
#### atBegin
Type: `Boolean`
Optional, defaults to false. If `atBegin` is false or unspecified, callback will
only be executed `delay` milliseconds after the last debounced-function call. If
`atBegin` is true, callback will be executed only at the first
debounced-function call. (After the throttled-function has not been called for
`delay` milliseconds, the internal counter is reset).
## Differences with original module
- Dependancy on jQuery is removed, so if you rely on GUIDs set by jQuery, plan
accordingly
- There is no standalone version available, so don’t rely on `$.throttle` and
`$.debounce` to be available
## Browser support
Tested in Chrome 72, Edge 15, Firefox 65 and should work in all modern browsers
([support based on Browserslist configuration](https://browserslist.dev/?q=bGFzdCAzIG1ham9yIHZlcnNpb25zLCBzaW5jZSAyMDE5LCBlZGdlID49IDE1LCBub3QgaWUgPiAw)).
## Test
For automated tests, run `npm run test:automated` (append `:watch` for watcher
support).
## License
MIT © [Ivan Nikolić](http://ivannikolic.com)
[ci]: https://github.com/niksy/throttle-debounce/actions?query=workflow%3ACI
[ci-img]: https://github.com/niksy/throttle-debounce/actions/workflows/ci.yml/badge.svg?branch=master
[browserstack]: https://www.browserstack.com/
[browserstack-img]: https://img.shields.io/badge/browser%20testing-BrowserStack-informational?logo=data:image/svg+xml;base64,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
[awesome]: https://github.com/parro-it/awesome-micro-npm-packages
[awesome-img]: https://awesome.re/mentioned-badge.svg
[jquery-throttle-debounce]: https://github.com/cowboy/jquery-throttle-debounce