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bmingles/switchExp.ts

Last active May 25, 2020 04:14
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Tagged Union Switch Expression
Raw
switchExp.ts
type Tagged<T extends string> = {
type: T
}
export function switchExp<
T extends Tagged<string>,
M extends { [P in T['type']]: T extends Tagged<P> ? (t: T) => any : never }
>(value: T, map: M): ReturnType<M[keyof M]> {
return map[value.type as keyof M](value)
}
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