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debounce

import { debounce } from 'patronum';
// or
import { debounce } from 'patronum/debounce';

debounce({ source, timeout })

Motivation

Method creates a new event, that will be triggered after some time. It is useful for handling user events such as scrolling, mouse movement, or keypressing. It is useful when you want to pass created event immediately to another method as argument.

Formulae

event = debounce({ source, timeout });
  • Wait for timeout after the last time source was triggered, then trigger event with payload of the source

Arguments

  1. source (Event<T> | Store<T> | Effect<T>) — Source unit, data from this unit used by the event
  2. timeout (number | Store<number>) — time to wait before trigger event

Returns

  • event (Event<T>) — New event, that triggered after delay

Example

import { createEvent } from 'effector';
import { debounce } from 'patronum/debounce';

const DEBOUNCE_TIMEOUT_IN_MS = 200;

const someHappened = createEvent<number>();
const debounced = debounce({
source: someHappened,
timeout: DEBOUNCE_TIMEOUT_IN_MS,
});

debounced.watch((payload) => {
console.info('someHappened now', payload);
});

someHappened(1);
someHappened(2);
someHappened(3);
someHappened(4);

// someHappened now 4

debounce({ source, timeout, target })

Motivation

This overload receives target as argument, that will be triggered after timeout. It is useful when you already have an unit that you need to trigger.

Formulae

event = debounce({ source, timeout, target });
  • Wait for timeout after the last time source was triggered and call target with data from the source

Arguments

  1. source (Event<T> | Store<T> | Effect<T>) — Source unit, data from this unit used to trigger target with payload of the source
  2. timeout (number | Store<number>) — time to wait before trigger event
  3. target (Event<T> | Store<T> | Effect<T>) — Target unit, data from the source will be passed to this unit

Returns

  • target (Event<T> | Store<T> | Effect<T>) — Target unit that was passed to input argument target

Example

import { createEvent, createStore } from 'effector';
import { debounce } from 'patronum/debounce';

const DEBOUNCE_TIMEOUT_IN_MS = 200;

const someHappened = createEvent<number>();
const target = createStore<number>(0);
const debounced = debounce({
source: someHappened,
timeout: DEBOUNCE_TIMEOUT_IN_MS,
target,
});

debounced.watch((payload) => {
console.info('someHappened now', payload);
});

target.watch((payload) => {
console.info('got data', payload);
});

someHappened(1);
someHappened(2);
someHappened(3);
someHappened(4);

// someHappened now 4
// got data 4

Example with timeout as store

import { createStore } from 'effector';
import { debounce } from 'patronum';

const DEBOUNCE_TIMEOUT_IN_MS = 200;

const changeTimeout = createEvent<number>();
const $timeout = createStore(DEBOUNCE_TIMEOUT_IN_MS).on(
changeTimeout,
(_, value) => value,
);
const someHappened = createEvent<number>();
const debounced = debounce({
source: someHappened,
timeout: $timeout,
});

debounced.watch((payload) => {
console.info('someHappened now', payload);
});

someHappened(1);
changeTimeout(400); // will be applied after next source trigger
someHappened(2);

setTimout(() => {
// console clear
}, 200);

setTimout(() => {
// someHappened now 2
}, 400);