36 lines
1.2 KiB
JavaScript
36 lines
1.2 KiB
JavaScript
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import {useRef, useEffect} from "react";
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// Hook to wrap event emitter on and removeListener in hook lifecycle
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export const useEventEmitter = (emitter, eventName, handler) => {
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// Create a ref that stores handler
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const savedHandler = useRef();
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// Update ref.current value if handler changes.
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// This allows our effect below to always get latest handler ...
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// ... without us needing to pass it in effect deps array ...
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// ... and potentially cause effect to re-run every render.
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useEffect(() => {
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savedHandler.current = handler;
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}, [handler]);
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useEffect(
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() => {
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// Make sure element supports on
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const isSupported = emitter && emitter.on;
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if (!isSupported) return;
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// Create event listener that calls handler function stored in ref
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const eventListener = event => savedHandler.current(event);
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// Add event listener
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emitter.on(eventName, eventListener);
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// Remove event listener on cleanup
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return () => {
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emitter.removeListener(eventName, eventListener);
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};
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},
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[eventName, emitter], // Re-run if eventName or emitter changes
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);
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};
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