Throttle and debounce functions.
npm install 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), but it’s
transferred to ES Modules and CommonJS format.
``sh`
npm install throttle-debounce --save
`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
`
`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
`
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 function:
`js
const debounceFunc = debounce(300, () => {
// Debounced function
});
debounceFunc(); // will not be invoked
debounceFunc.cancel({ upcomingOnly: true });
debounceFunc(); // will be invoked
`
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 allcallback
arguments are passed through, as-is, to 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. Ifdelay
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 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 is false (at end), schedule callback to execute afterdelay ms.
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 allcallback
arguments are passed through, as-is, to when the debounced-function
is executed.
#### atBegin
Type: Boolean
Optional, defaults to false. If atBegin is false or unspecified, callback willdelay
only be executed milliseconds after the last debounced-function call. IfatBegin is true, callback will be executed only at the firstdelay
debounced-function call. (After the throttled-function has not been called for milliseconds, the internal counter is reset).
- 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
Tested in Chrome 72, Edge 15, Firefox 65 and should work in all modern browsers
(support based on Browserslist configuration).
For automated tests, run npm run test:automated (append :watch` for watcher
support).
MIT © Ivan Nikolić
[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