ghost-portal/packages/react-hooks/src/useFormField.ts
Keith Ingram 3afceac9d1
Parachains app (#2308)
* parachains app

* fin

* fin

* rec changes

* Fix sudo lookup

* sudoKey is already a string

* fix CI

* Fix build, re-gen i18n

Co-authored-by: Jaco Greeff <jacogr@gmail.com>
2020-03-02 08:48:29 +01:00

30 lines
791 B
TypeScript

// Copyright 2017-2020 @polkadot/react-hooks authors & contributors
// This software may be modified and distributed under the terms
// of the Apache-2.0 license. See the LICENSE file for details.
import { useMemo, useState } from 'react';
type FormField<T> = [
T | null,
boolean,
(_?: T | null) => void
];
function isTruthy<T> (value?: T | null): boolean {
return !!value;
}
export default function useFormField<T> (defaultValue: T | null, validate: (_?: T | null) => boolean = (): boolean => true): FormField<T> {
const [value, setValue] = useState<T | null>(defaultValue);
const isValid = useMemo(
(): boolean => isTruthy<T>(value) && validate(value),
[value]
);
return [
value,
isValid,
(value?: T | null): void => setValue(value || null)
];
}