mirror of
https://github.com/streamich/react-use.git
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30abe2b22e
feat(useFirstMountState): hook to track if render is first; feat(useRendersCount): hook to track renders count; refactor(useUpdateEffect): now uses useFirstMountState hook; refactor(usePreviousDistinct): now uses with useFirstMountState hook; docs: update readme;
20 lines
618 B
TypeScript
20 lines
618 B
TypeScript
import { useRef } from 'react';
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import { useFirstMountState } from './useFirstMountState';
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export type Predicate<T> = (prev: T | undefined, next: T) => boolean;
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const strictEquals = <T>(prev: T | undefined, next: T) => prev === next;
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export default function usePreviousDistinct<T>(value: T, compare: Predicate<T> = strictEquals): T | undefined {
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const prevRef = useRef<T>();
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const curRef = useRef<T>(value);
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const isFirstMount = useFirstMountState();
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if (!isFirstMount && !compare(curRef.current, value)) {
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prevRef.current = curRef.current;
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curRef.current = value;
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}
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return prevRef.current;
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}
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