Created
June 20, 2019 09:43
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React Hooks
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import { createRef, useState, useEffect, useContext } from 'react' | |
export function useReducer(reducer, initialArg, init) { | |
const [stateRef] = useState(() => { | |
if (init === undefined) { | |
return createRef(initialArg) | |
} else { | |
return createRef(init(initialArg))) | |
} | |
}) | |
const dispatch = useCallback((action) => { | |
stateRef.current = reducer(stateRef.current, action) | |
}, [stateRef, reducer]) | |
return [stateRef.current, dispatch] | |
} | |
export function useCallback(fn, deps) { | |
return useMemo(() => fn, deps) | |
} | |
export function useMemo(create, deps) { | |
const [value, setValue] = useState(create) | |
useEffect(() => { | |
setValue(create()) | |
}, deps) | |
return value | |
} | |
export function useRef(initialValue) { | |
const [ref] = useState(() => createRef(initialValue)) | |
return ref | |
} | |
export function useImperativeHandle(ref, createHandler, deps) { | |
} |
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