@webreflection/signal

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A minimalistic signals implementation, derived from the post Signals: the nitty-gritty, which size, once minified and brotlied, is 528 bytes.

• no automatic effect disposal except when an outer effect has inner effects and the outer effect dispose() is invoked
• computed are lazily initialied but updated per each signal change they depend on, unless a batch operation is updating all inner signals at once
• no fancy features from other libraries

For anything more complex please check usignal out.

exports

• signal(value) to create a new signal with a reactive .value
• computed(fn[, initialValue]) to create a computed signal with a read-only .value
• effect(fn) to create an effect and return a dispose function
• batch(fn) to update multiple signals at once and invoke related effects once
• untracked(fn) to make a callback that can read some signals without subscription to them
• Signal to compare via instanceof Signal instances
• Computed to compare via instanceof Computed instances

Computed accepts an initial value to pass to the callback. The callback will keep receiving the previous value on each new invoke.

example

// import {signal, effect} from 'https://unpkg.com/@webreflection/signal';
// const {signal, effect} = require('@webreflection/signal');
import {signal, effect} from '@webreflection/signal';

const single = signal(1);
const double = signal(10);
const triple = signal(100);

const dispose1 = effect(() => {
  console.log(`
  #1 effect
    single: ${single}
    double: ${double}
  `);
});

const dispose2 = effect(() => {
  console.log(`
  #2 effect
    double: ${double}
    triple: ${triple}
  `);
});

++double.value;
// logs single 1, double 11
// logs double 11, triple 100

dispose2();

++double.value;
// logs single 1, double 11