useMemo.js 354 B

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  1. import * as React from 'react';
  2. export default function useMemo(getValue, condition, shouldUpdate) {
  3. var cacheRef = React.useRef({});
  4. if (!('value' in cacheRef.current) || shouldUpdate(cacheRef.current.condition, condition)) {
  5. cacheRef.current.value = getValue();
  6. cacheRef.current.condition = condition;
  7. }
  8. return cacheRef.current.value;
  9. }