@alcadica/signal

@alcadica/signal

• @alcadica/signal
  • Install
  • Examples
  • Licence

A signal is basically a function with a subscription system bound to it.

Install

npm i --save @alcadica/signal

Examples

A real-life example:

// file CounterAspect.ts
import signal from '@alcadica/signal';

export const increment: signal = signal();
export const dispose: signal = signal();
export const stateDidChange: signal = signal();

export const state = {
  counter: 0
}

export default {
  dispose,
  increment, 
  state,
  stateDidChange
}

increment.connect(() => {
  state.counter++;
});

// my-component.tsx
import * as React from 'react';
import CounterAspect from './CounterAspect';

export class MyComponent extends React.Component<any, any> {
  public state: any = CounterAspect.state;
  
  public componentDidMount(): void {
    const signalid = CounterAspect.stateDidChange.connect((key, value) => this.setState({ [key]: value }));
    CounterAspect.dispose.connect(() => CounterAspect.stateDidChange.disconnect(signalid));
  }

  public componentWillUnmount(): void {
    CounterAspect.dispose();
  }
  
  public render(): JSX.Element {
    return (
      <div onClick={CounterAspect.increment}>{CounterAspect.state.counter}</div>
    )
  }
}

A signal subscription can also be consumed only once

import signal from '@alcadica/signal';

const foo = { bar: 0 }
const baz = signal<[number]>();

baz.connectOnce(arg => foo.bar = foo.bar + arg);

baz(1) // foo.bar is 1
baz(1) // foo.bar is still 1
baz(1) // foo.bar is still 1 again

Licence

MIT