xevt
v0.9.0
Published
another event emiiter.
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xevt
another event emiiter.
features:
- can listen async/conjoined event.
- support to mixed async/sync handlers
- conditional event handlers.
- return unscriber when you subscribe an event.
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.on("event", async () => {
result++;
});
await emitter.emit("event");
Conditional event handlers.
IMPORTANT:
- NOT supported in conjoined events.
- NOT supported any arguments in handlers.
- It will be executed after the triggered event finished. (Blocking mode.)
const emitter = new Xevt();
const result: any[] = [];
emitter.on("event", async (arg: number) => {
result.push(arg);
return arg % 2 === 0;
});
emitter.on("event", {
true: async () => {
result.push("first");
},
});
emitter.on("event", {
false: async () => {
result.push("fail");
},
});
emitter.on("event", {
true: () => {
result.push(100);
},
false: () => {
result.push(99);
},
});
emitter.emit("event", 1);
emitter.emit("event", 2);
await delay(10);
// [1, "fail", 99, 2, "first", 100]
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
Non-blocking in default.
const emitter = new Xevt();
const result: number[] = [];
emitter.on("event", (data) => {
result.push(data);
});
emitter.on(
"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, 1, 2, 3, 4, 0, 1, 2, 3, 4]
Blocking mode.
const emitter = new Xevt();
const result: number[] = [];
emitter.on("event", (data) => {
result.push(data);
});
emitter.on(
"event",
// deno-lint-ignore require-await
async (data) =>
new Promise((res) => {
setTimeout(() => {
result.push(data);
res(true);
}, 1);
}),
{ async: true },
);
for (let i = 0; i < 5; i++) {
emitter.emit("event", i);
}
await delay(15);
// [0, 0, 1, 1, 2, 2, 3, 3, 4, 4]
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.