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anthowave/custom-type-check.ts

Created December 2, 2020 12:50
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TS - determine if var is type of custom type
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custom-type-check.ts
const stringLitArray = <L extends string>(arr: L[]) => arr;
const linkTypes = stringLitArray(['a', 'link']);
export type LinkType = (typeof linkTypes)[number];
const isLinkType = (x: any): x is LinkType => linkTypes.includes(x);
let link = 'a';
if (isLinkType('a')) {
console.log("The current link is of type 'LinkType'");
}
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More example; How to implement a generic ValueOf<T​> helper type in TypeScript.

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