69 lines
1.9 KiB
TypeScript
69 lines
1.9 KiB
TypeScript
/**
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* How to use a Signal:
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*
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* Create a signal with primitives:
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* const nameSignal = new Signal<string>()
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* const countSignal = new Signal<number>()
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*
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* Create a signal with objects:
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* const chatSignal = new Signal<{ username: string, message: string }>()
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*
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* Create a signal with no data (void):
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* const clickSignal = new Signal<void>()
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* const clickSignal2 = new Signal() // Defaults to void
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*
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* Connect to the signal:
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* const disconnect = chatSignal.connect((data) => {
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* const {username, message} = data;
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* console.log(`${username} said "${message}"`);
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* })
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*
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* Emit a signal:
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* nameSignal.emit("Alice")
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* countSignal.emit(42)
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* chatSignal.emit({ username: "Chad", message: "Hey everyone, how's it going?" });
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* clickSignal.emit() // No argument for void signals
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*
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* Forward a signal:
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* const relaySignal = new Signal<{ username: string, message: string }>()
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* const disconnectRelay = chatSignal.connect(relaySignal)
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* // Now, when chatSignal emits, relaySignal will also emit the same data
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*
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* Disconnect a single listener:
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* disconnect(); // The disconnect function is returned when you connect to a signal
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*
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* Disconnect all listeners:
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* chatSignal.disconnect()
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*/
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export class Signal<T = void> {
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private listeners: Array<(data: T) => void> = []
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connect(listenerOrSignal: Signal<T> | ((data: T) => void)) {
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let listener: (data: T) => void
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// If it is a signal, forward the data to the signal
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if (listenerOrSignal instanceof Signal) {
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listener = (data: T) => listenerOrSignal.emit(data)
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} else {
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listener = listenerOrSignal
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}
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this.listeners.push(listener)
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return () => {
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this.listeners = this.listeners.filter((l) => l !== listener)
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}
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}
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emit(data: T) {
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for (const listener of this.listeners) {
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listener(data)
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}
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}
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disconnect() {
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this.listeners = []
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}
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}
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