Converted to TypeScript and ES6 modules
The "emitter" provides pub/sub options
$ npm install @mdaemon/emitter --saveconst Emitter = require("@mdaemon/emitter/dist/emitter.cjs");import Emitter from "@mdaemon/emitter/dist/emitter.mjs";<script type="text/javascript" src="/path_to_modules/dist/emitter.umd.js">/* this is more typically used as a prototype for a class or object
* class Messages extends Emitter {}
*
* or
*
* function Messages() {
* Object.assign(this, new Emitter());
* }
*/
// maxListeners and maxOnceListeners default to 50 and are immutable once set
const emitter = new Emitter({
maxListeners: 20,
maxOnceListeners: 40
});
emitter.on("test", "namespace", (input) => {
console.log(input);
});
emitter.emit("test", "this is a test");
// this is a test
emitter.off("test", "namespace");
emitter.emit("test", "this will go nowhere");
// if you pass a function as the second parameter, the function will be registered as part of an "all" namespace
emitter.on("test", (input) => {
console.log(input, "this gets called");
});
emitter.emit("test", "calling all");
// calling all this gets called
// your flavor of pub/sub may vary
// emitter.register === emitter.on === emitter.subscribe
// emitter.unregister === emitter.off === emitter.unsubscribe
// emitter.trigger === emitter.emit === emitter.publish
emitter.once("only-receive-this-once", (input) => {
console.log(input);
});
emitter.trigger("only-receive-this-once", "this was received once, and then removed from memory");
// this was received once, and then removed from memory
// onMany allows you to register/subscribe multiple items at once
emitter.onMany("namespace", {
"test": (input) => { console.log("test", input); },
"test2": (input) => { console.log("test2", input); }
});
emitter.emit("test", "my test");
// test my test
emitter.emit("test2", "another test");
// test2 another test
// isRegistered checks if an event+namespace combination is registered
emitter.isRegistered("test2", "namespace");
// true
// propagate is a reverse parameter of trigger/emit/publish
emitter.propagate("another test", "test2");
// test2 another test
// offAll will remove all subscriptions for a given namespace
emitter.offAll("namespace");
emitter.emit("test", "nothing will be logged");
// a priority property can be added to the end of the paramters
emitter.on("test3", "namespace", () => {
console.log("this will be logged last");
}, Emitter.LOW_PRIORITY);
emitter.on("test3", "namespace", () => {
console.log("this will be logged first");
}, Emitter.HIGH_PRIORITY);
emitter.emit("test3");
// this will be logged first
// this will be logged last
// once registrations do not have a priority, because the event will only execute oncePublished under the LGPL-2.1 license.
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