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| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 | 35x 2156x | import { StringTypeValidator } from './../types';
/**
* Make a validator function for a string-based type.
*
* This takes an array of allowed string values, and returns a function that
* indicates whether the given value is one of the allowed values. This is
* useful for when you have a prop whose type is a set of string constants, and
* you need a validator for that prop.
*
* @example
* import { ButtonAction } from './types';
* import { ButtonActions } from './constants';
* import { makeStringTypeValidator } from './utils/stringTypeValidator';
* const isButtonAction = makeStringTypeValidator( ButtonActions );
*
* // in a component definition:
* props: {
* action: {
* type: String as PropType<ButtonAction>
* validator: isButtonAction
* }
* }
*
* // You can shorten this by inlining the isButtonAction variable, but
* // then you have to explicitly specify the type to avoid errors:
* props: {
* action: {
* type: String as PropType<ButtonAction>
* validator: makeStringTypeValidator<ButtonAction>( ButtonActions )
* }
* }
*
* @param allowedValues Allowed values
* @return Function that takes a value and returns whether it is
* one of allowedValues
*/
export function makeStringTypeValidator<T extends string>(
allowedValues: readonly T[]
) : StringTypeValidator<T> {
return ( s: unknown ) : s is T => typeof s === 'string' &&
( allowedValues as readonly string[] ).indexOf( s ) !== -1;
}
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