tseep
Version:
Fastest event emitter in the world
127 lines (93 loc) • 4.26 kB
Markdown
[](https://www.npmjs.com/package/tseep)
[](https://GitHub.com/Morglod/tseep/)
# tseep
Because there are N fastest event emitters. And we are fastest (feb 2023) 😏.
Up to **x12** faster than `eventemitter3` in terms of "classic api event emitters" (currently fastest for not classic too).
- Fully typed args of `emit` method based on events map
- Fully implements `NodeJS.EventEmitter` type & standart, provides interface
- Worlds fastest pure-js `EventEmitter`
- Fully tested with eventemitter3 tests
- No external deps
- Only 381 bytes size in real app (brotlied)
- No eval implemented
[how it works](./docs/how_it_works_en.md)
## Benchmarks
emit-multiple-listeners:
```
tseep 89,030,882 ops/sec
tseep no-eval 15,235,353 ops/sec
emitix 6,201,874 ops/sec
fastemitter 5,981,406 ops/sec
EventEmitter3 5,698,255 ops/sec
tsee 5,163,550 ops/sec
EventEmitter2 4,588,433 ops/sec
EventEmitter1 4,437,743 ops/sec
mitt 3,587,734 ops/sec
event-emitter 3,508,490 ops/sec
contra/emitter 2,183,943 ops/sec
Fastest is [ 'tseep' ]
```
[benchmarks](./benchmarks/README.md)
Make an issue to include yours event emitter, lets find the fastest!
## Install & use
```
npm i tseep
```
Simple usage:
```ts
import { EventEmitter } from "tseep";
const events = new EventEmitter<{
foo: (a: number, b: string) => void;
}>();
// foo's arguments is fully type checked
events.emit("foo", 123, "hello world");
```
### Use no-eval version
There is no user code evaluated so its complete safe to use with-eval version.
But in some cases (eg chrome's extensions), you just cant use it.
For this cases there is no-eval version:
```ts
import { EventEmitter } from "tseep/lib/ee-safe"; // no-eval version
import { EventEmitter } from "tseep/lib/fallback"; // or with autofallback
// same api
```
"tseep/lib/fallback" may bundle both versions which may result in bigger app bundle size.
## Api
`EventEmitter<T>` where `T` extends `{ [eventName]: Call signature }`.
`EventEmitter.emit`'s args is fully typed based on events map.
!! **`__proto__`** event name is restricted (type guard exists) !!
By default listeners are not bound to EventEmitter, so you may get some problems around inheritance.
First of all, better use incapsulation. Its faster, safer, clear.
Other variant is to use addListenerBound/removeListenerBound.
Its 2-3x slower for add/remove operation but than you will have proper 'this' context inside listener.
```ts
// Listener = (...args: any[]) => Promise<any>|void
// EventMap extends { [event in (string|symbol)]: Listener }
class EventEmitter<EventMap> {
readonly maxListeners: number;
readonly _eventsCount: number;
emit(event: EventKey, ...args: ArgsN<EventMap[EventKey]>): boolean;
on(event: EventKey, listener: EventMap[EventKey]): this;
once(event: EventKey, listener: EventMap[EventKey]): this;
addListener(event: EventKey, listener: EventMap[EventKey], argsNum?: ArgsNum<EventMap[EventKey]>): this;
removeListener(event: EventKey, listener: EventMap[EventKey]): this;
hasListeners(event: EventKey): boolean;
prependListener(event: EventKey, listener: EventMap[EventKey]): this;
prependOnceListener(event: EventKey, listener: EventMap[EventKey]): this;
off(event: EventKey, listener: EventMap[EventKey]): this;
removeAllListeners(event?: EventKey): this;
setMaxListeners(n: number): this;
getMaxListeners(): number;
listeners(event: EventKey): EventMap[EventKey][];
rawListeners(event: EventKey): EventMap[EventKey][];
eventNames(): Array<string | symbol>;
listenerCount(type: EventKey): number;
// special methods that are a bit slower than addListener/removeListener
// but they binds listeners to current EventEmitter or custom object
addListenerBound(event: EventKey, listener: EventMap[EventKey], bindTo?: any = this, argsNum?: ArgsNum<EventMap[EventKey]>): this;
removeListenerBound(event: EventKey, listener: EventMap[EventKey]): this;
}
```
## License
MIT