@bscotch/emitter
v0.2.1
Published
Extension of eventemitter2, adding typed events.
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EventEmitter2 (with types!)
Existing EventEmitter libraries typically do not provide much support for indicating what events and payloads are available on a given emitter. This library adds that support to the popular EventEmitter2 library.
Usage
Events can be described as a string (when just the event name is needed because there is no expected payload) or as an object with a payload:
import {createEmitter} from '@bscotch/emitter';
type MySimpleEvent = "my-simple-event";
interface MyComplexEvent {
name: "my-complex-event";
// The payload must be a *tuple* of the arguments that will
// be passed to the event handler.
payload: [arg0: string, arg1: { foo: number }];
}
// For best results, events should be collected in a tuple type
type MyEvents = [MySimpleEvent, MyComplexEvent];
const emitter = createEmitter<MyEvents>();
// Now you'll have typed emitter methods!
emitter.on('my-simple-event', () => {});
emitter.emit('my-simple-event');
emitter.on('my-complex-event', (arg0, arg1) => {}); // <- callback is typed!
emitter.emit('my-complex-event', 'foo', { foo: 1 }); // <- arguments are typed!