83a2ddedd4
* Add React.emomo to some components * Linting * useCallback for callbacks * Additional useCallback impl.
31 lines
846 B
TypeScript
31 lines
846 B
TypeScript
// Copyright 2017-2020 @polkadot/react-hooks authors & contributors
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// This software may be modified and distributed under the terms
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// of the Apache-2.0 license. See the LICENSE file for details.
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import { useCallback, useMemo, useState } from 'react';
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type FormField<T> = [
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T | null,
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boolean,
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(_?: T | null) => void
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];
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function isTruthy<T> (value?: T | null): boolean {
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return !!value;
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}
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export default function useFormField<T> (defaultValue: T | null, validate: (_?: T | null) => boolean = (): boolean => true): FormField<T> {
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const [value, setValue] = useState<T | null>(defaultValue);
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const isValid = useMemo(
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(): boolean => isTruthy<T>(value) && validate(value),
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[value]
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);
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const setter = useCallback((value?: T | null): void => setValue(value || null), []);
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return [
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value,
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isValid,
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setter
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];
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}
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