A type checked signal library for TypeScript (and JavaScript)
npm install typed-signals
A type-checked signal library written in TypeScript, usable from plain JavaScript as well. This is a TypeScript port of this excellent C++11 version:
Performance of a C++11 Signal System.
Of course, some changes have been made to make it work with TypeScript.
The original unit tests and additional ones are running automatically on Travis-CI
#### Fair Warning
With version 2, the target is now es2015, so if you want to support older browser, you'll have to ensure that this module is being transpiled to an older es version during your build-process.
npm install typed-signals --save`
$3
`typescript
import { Signal } from "typed-signals";
// Create a new signal, defining the function signature of handlers :
let mySignal = new Signal<(n: number, b: boolean, s: string) => void>();
//Register a handler:
let connection = mySignal.connect((n, b, s)=> console.log(Called: ${n} ${b} ${s}));
// Emit a signal:
mySignal.emit(42, true, 'Galactic Gargleblaster');
// Disconnect a handler:
connection.disconnect();
`
$3
`typescript
import { Signal, SignalConnections } from "typed-signals";
let mySignal = new Signal<() => void>();
// Disable and re-enable handlers
function handler42() {}
let connection = mySignal.connect(handler42);
connection.enabled = false;
mySignal.emit(); // won't call handler42
connection.enabled = true;
mySignal.emit(); // will call handler42
// Remember multiple connections and disconnect them all at once:
let connections = new SignalConnections();
connections.add(mySignal.connect(()=>{}));
connections.add(mySignal.connect(()=>{}));
connections.add(mySignal.connect(()=>{}));
connections.disconnectAll();
// Or disconnect all handlers of a signal:
mySignal.disconnectAll();
`
$3
`typescript
import { Signal } from "typed-signals";
let mySignal = new Signal<() => void>();
// Handlers are called in the order in which they are added:
mySignal.connect(()=>console.log('first'));
mySignal.connect(()=>console.log('second'));
mySignal.disconnectAll();
// Second parameter to connect is an order value. A higher order value means later execution:
mySignal.connect(()=>console.log('second'), 1);
mySignal.connect(()=>console.log('first'), 0);
`
$3
Collectors can be used to stop processing further handlers depending on the return value of a handler and/or to collect return values of those handlers.
Built-in Collectors:
- CollectorLast
- Returns the result of the last signal handler from a signal emission.
- CollectorUntil0
- Keep signal emissions going while all handlers return true.
- CollectorWhile0
- Keep signal emissions going while all handlers return false.
- CollectorArray
- Returns the result of the all signal handlers from a signal emission in an array.
THandler must be the same function signature as the signal. Here is an example:
`typescript
import { Signal, CollectorLast } from "typed-signals";
let mySignal = new Signal<() => string>();
let collector = new CollectorLast<() => string>(mySignal);
mySignal.connect(()=> 'Hello World');
mySignal.connect(()=> 'Foo Bar');
collector.emit(); // calls signal.emit();
console.log(collector.getResult()); // 'Foo Bar'
``