Evnty

0-Deps, simple, fast, for browser and node js anonymous event library

Interface

declare type Unsubscribe = () => void;
declare type Listener = (...args: any[]) => void;
declare type Dispose = () => void;
declare type Filter = (...args: any[]) => boolean;
declare type Mapper = <T = any>(...args: any[]) => T;
declare type Reducer = <T = any>(value: any, ...args: any[]) => T;

declare class Event {
    static merge(...events: Event[]): Event;
    static interval(interval: number): Event;

    readonly size: Number;

    constructor(dispose?: Dispose);
    has(listener: Listener): boolean;
    off(listener: Listener): void;
    on(listener: Listener): Unsubscribe;
    once(listener: Listener): Unsubscribe;
    clear(): void;
    toPromise(): Promise<any[]>;
    filter(filter: Filter): Event;
    map(mapper: Mapper): Event;
    reduce(reducer: Reducer, init: any): Event;
}

Usage

import event from 'evnty';

function handleClick({ button }) {
  console.log('Clicked button is', button);
}
const clickEvent = event();
const unsubscribe = clickEvent.on(handleClick);

const keyPressEvent = event();

function handleInput({ button, key }) {

}

const inputEvent = Event.merge(clickEvent, keyPressEvent);
inputEvent.on(handleInput);

function handleLeftClick() {
  console.log('Left button is clicked');
}
const leftClickEvent = clickEvent.filter(({ button }) => button === 'left');
leftClickEvent.on(handleLeftClick);


clickEvent({ button: 'right' });
clickEvent({ button: 'left' });
clickEvent({ button: 'middle' });
keyPressEvent({ key: 'A' });
keyPressEvent({ key: 'B' });
keyPressEvent({ key: 'C' });

leftClickEvent.off(handleLeftClick);
unsubscribe();

License

License The MIT License Copyright (c) 2021 Ivan Zakharchanka