Steps for generating a signal that postpones the primary signal and promptly resets

Question

Steps for generating a signal that postpones the primary signal and promptly resets

I am looking to create a signal that will automatically switch to an underlying signal or memo after a specific delay, and reset immediately if the primary signal is cleared. The code snippet below illustrates my desired functionality.

import { render } from "solid-js/web";
import { For, createSignal, createEffect } from "solid-js";

function Counter() {
   const [s, setS] = createSignal(undefined)
   const [delayedS, delayedSetS] = createSignal(undefined)


   setTimeout(() => {
     setS(10)
   }, 1000)

   setTimeout(() => {
     setS(undefined)
   }, 3000)

   createEffect(() => {
      let res = s()
      if (res !== undefined) {
         setTimeout(() => delayedSetS(res), 1000)
      } else {
         delayedSetS(undefined)
      }
   })

  return (<>
    <span> S {s()} </span>
    <span> Delayed S {delayedS()}</span>
    </>)
}

render(() => <Counter />, document.getElementById("app"));

The above implementation works fine, but I'm wondering if this is the best approach. I haven't explored using createDeferred for this function as it involves a scheduler that I'm not familiar with.

typescript solid-js

Answer 1

Answer №1

Your approach was completely valid.

While the createDeferred function may seem suitable for a similar purpose, it would not produce the desired outcome in this scenario due to the following reasons:

The timeout specified in createDeferred does not represent an exact waiting period before triggering updates; rather, it serves as a maximum idle time for the browser.
The timeout would occur prior to updating the signal to undefined and other values.

const delayedS = createDeferred(s)

For manipulating signals, a more favorable option is to use createComputed. This method involves pure computation similar to createMemo, ensuring immediate execution before applying effects. Although in straightforward cases there might not be a noticeable distinction compared to using effects, utilizing an effect for signal manipulation could potentially lead to excessive updates.

  createComputed(
    on(s, (v) => {
      if (v) setTimeout(() => setDelayedS(v), 1000);
      else setDelayedS();
    })
  );

In addition, cancelling the timeout upon setting to

undefined</code instantly can help mitigate timing inconsistencies.</p>
<pre class="lang-js"><code>  let timeoutId = 0;
  createComputed(
    on(s, (v) => {
      if (v) timeoutId = setTimeout(() => setDelayedS(v), 1000);
      else {
        setDelayedS();
        clearTimeout(timeoutId);
      }
    })
  );
  onCleanup(() => clearTimeout(timeoutId));

Answer 2

Your approach was completely valid.

While the createDeferred function may seem suitable for a similar purpose, it would not produce the desired outcome in this scenario due to the following reasons:

The timeout specified in createDeferred does not represent an exact waiting period before triggering updates; rather, it serves as a maximum idle time for the browser.
The timeout would occur prior to updating the signal to undefined and other values.

const delayedS = createDeferred(s)

For manipulating signals, a more favorable option is to use createComputed. This method involves pure computation similar to createMemo, ensuring immediate execution before applying effects. Although in straightforward cases there might not be a noticeable distinction compared to using effects, utilizing an effect for signal manipulation could potentially lead to excessive updates.

  createComputed(
    on(s, (v) => {
      if (v) setTimeout(() => setDelayedS(v), 1000);
      else setDelayedS();
    })
  );

In addition, cancelling the timeout upon setting to

undefined</code instantly can help mitigate timing inconsistencies.</p>
<pre class="lang-js"><code>  let timeoutId = 0;
  createComputed(
    on(s, (v) => {
      if (v) timeoutId = setTimeout(() => setDelayedS(v), 1000);
      else {
        setDelayedS();
        clearTimeout(timeoutId);
      }
    })
  );
  onCleanup(() => clearTimeout(timeoutId));

Answer 3

Answer №2

If you're looking to add delayed reactive functionality, consider utilizing the @solid-primitives/scheduled package.

import {createMemo, createSignal} from 'solid-js';
import {createScheduled, throttle} from '@solid-primitives/scheduled';

const [count, setCount] = createSignal(0);
const scheduled = createScheduled(callback => throttle(callback, 1000)); // introducing a delay of 1000 ms

const debouncedCount = createMemo(
  (previousCount) => scheduled() ? count() : previousCount,
  0
);

createEffect(() => {
  // The output of debouncedCount will only change every second, no matter how many times setCount is called.
  console.log(debouncedCount());
});

In this setup, calling setCount multiple times will result in updates to debouncedCount occurring at intervals of one second. Additionally, there are other scheduling functions like debounce, as well as modifiers such as leading.

To see these concepts in action, visit the demo on the mentioned page showcasing the various scheduling options available.

Answer 4

If you're looking to add delayed reactive functionality, consider utilizing the @solid-primitives/scheduled package.

import {createMemo, createSignal} from 'solid-js';
import {createScheduled, throttle} from '@solid-primitives/scheduled';

const [count, setCount] = createSignal(0);
const scheduled = createScheduled(callback => throttle(callback, 1000)); // introducing a delay of 1000 ms

const debouncedCount = createMemo(
  (previousCount) => scheduled() ? count() : previousCount,
  0
);

createEffect(() => {
  // The output of debouncedCount will only change every second, no matter how many times setCount is called.
  console.log(debouncedCount());
});

In this setup, calling setCount multiple times will result in updates to debouncedCount occurring at intervals of one second. Additionally, there are other scheduling functions like debounce, as well as modifiers such as leading.

To see these concepts in action, visit the demo on the mentioned page showcasing the various scheduling options available.

Steps for generating a signal that postpones the primary signal and promptly resets

Answer №1

Answer №2

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