evnty's Introduction

Prioritized Evnty

Based on https://github.com/3axap4eHko/evnty

Only fires event to the most recently added listener. Example:

import event from "./src/index";

const evt = event();

const handler1 = (info: string) => console.log(`Handler 1 returned: ` + info);
const unsubscribe1 = evt.on(handler1);

const handler2 = (info: string) => console.log(`Handler 2 returned: ` + info);
const unsubscribe2 = evt.on(handler2);

const handler3 = (info: string) => console.log(`Handler 3 returned: ` + info);
const unsubscribe3 = evt.on(handler3);

evt("something");

yields:

$ ts-node test.ts
Handler 3 returned: something

Interface

declare type Unsubscribe = () => void;
declare type Listener = (...args: any[]) => void;
declare type Dispose = () => void;

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;
}

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();