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xevt

another event emiiter.

features:

  • can listen async/conjoined event.
  • support to mixed async/sync handlers.
  • return unscriber when you subscribe an event.

Coverage Status License: MIT

Installation

npm install xevt

Then:

import { Xevt } from "xevt";

Usage

Basic usage

const emitter = new Xevt();

let result = 0;
emitter.on("event", () => {
  result++;
});
emitter.emit("event");

Async event

const emitter = new Xevt();

let result = 0;
emitter.onAsync("event", async () => {
  result++;
});
await emitter.emit("event");

Conjoined event

IMPORTANT: conjoined events are not supported any arguments in handlers.

const emitter = new Xevt();

let count = 0;
emitter.on(["event1", "event2"], () => {
  count++;
});
emitter.emit("event1");
emitter.emit("event2");

console.log(count); // 1

Mixed async/sync handlers

const emitter = new Xevt();
const result: number[] = [];
emitter.on("event", (data) => {
  result.push(data);
});
emitter.onAsync(
  "event",
  async (data) =>
    new Promise((res) => {
      setTimeout(() => {
        result.push(data);
        res(true);
      }, 10);
    }),
);

for (let i = 0; i < 5; i++) {
  emitter.emit("event", i);
}

// [0, 0, 1, 1, 2, 2, 3, 3, 4, 4]
const emitter = new Xevt();
const result: number[] = [];
emitter.conjoin(["event1", "event2"], async () => {
  result.push(1);
});
emitter.conjoinAsync(["event1", "event2"], async () => {
  result.push(2);
});

for (let i = 0; i < 5; i++) {
  emitter.emit("event1");
  emitter.emit("event2");
}

// [1, 2, 1, 2, 1, 2, 1, 2, 1, 2]

Return unscriber after registered an event

const emitter = new Xevt();
const result: number[] = [];
const unscribe = emitter.on("event", (arg: number) => {
  result.push(arg);
});
unscribe();
const emitter = new Xevt();
const result: number[] = [];
const unscribe = emitter.conjoin(["event1", "event2"], () => {
  result.push(1);
});
unscribe();

Debug mode

const emitter = new Xevt();
emitter.debug = true;

Then you can see the debug information in the console.

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