40 lines
1.4 KiB
TypeScript
40 lines
1.4 KiB
TypeScript
/*
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Copyright 2020 The Matrix.org Foundation C.I.C.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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import { useEffect, useRef } from "react";
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import { Dispatcher } from "flux";
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import { ActionPayload } from "../dispatcher/payloads";
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// Hook to simplify listening to flux dispatches
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export const useDispatcher = (dispatcher: Dispatcher<ActionPayload>, handler: (payload: ActionPayload) => void) => {
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// Create a ref that stores handler
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const savedHandler = useRef((payload: ActionPayload) => {});
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// Update ref.current value if handler changes.
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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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// Create event listener that calls handler function stored in ref
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const ref = dispatcher.register((payload) => savedHandler.current(payload));
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// Remove event listener on cleanup
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return () => {
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dispatcher.unregister(ref);
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};
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}, [dispatcher]);
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};
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