39 lines
1.4 KiB
JavaScript
39 lines
1.4 KiB
JavaScript
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/**
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* @internal
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* Combine two event callbacks into a single callback function that calls each one in order.
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*
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* Usage example:
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* ```ts
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* state.slot.onChange = mergeCallbacks(state.slot.onChange, ev => {
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* // Handle onChange
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* });
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* ```
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*
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* The primary use is to avoid the need to capture an existing callback (`state.slot.onChange` in the example) to a
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* local variable before replacing with a new listener that calls the existing one. This helps avoid bugs like:
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* * Infinite recursion by calling the re-assigned state.slot.onChange if it's not captured to a local variable.
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* * Missing a call to the original onChange due to an early return or other conditional.
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*
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* If you need a callback that is stable between renders, wrap the result in {@link useEventCallback}.
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*
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* @param callback1 - The first callback to be called, or undefined
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* @param callback2 - The second callback to be called, or undefined
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*
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* @returns A function that that calls the provided functions in order
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*/ "use strict";
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Object.defineProperty(exports, "__esModule", {
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value: true
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});
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Object.defineProperty(exports, "mergeCallbacks", {
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enumerable: true,
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get: function() {
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return mergeCallbacks;
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}
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});
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function mergeCallbacks(callback1, callback2) {
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return (...args)=>{
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callback1 === null || callback1 === void 0 ? void 0 : callback1(...args);
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callback2 === null || callback2 === void 0 ? void 0 : callback2(...args);
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};
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}
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