type-fest/test-d/set-optional.ts

19 lines
889 B
TypeScript

import {expectNotAssignable, expectType} from 'tsd';
import type {SetOptional} from '../index';
// Update one required and one optional to optional.
declare const variation1: SetOptional<{a: number; b?: string; c: boolean}, 'b' | 'c'>;
expectType<{a: number; b?: string; c?: boolean}>(variation1);
// Update two required to optional.
declare const variation2: SetOptional<{a: number; b: string; c: boolean}, 'a' | 'b'>;
expectType<{a?: number; b?: string; c: boolean}>(variation2);
// Three optional remain optional.
declare const variation3: SetOptional<{a?: number; b?: string; c?: boolean}, 'a' | 'b' | 'c'>;
expectType<{a?: number; b?: string; c?: boolean}>(variation3);
// Fail if type changes even if optional is right.
declare const variation4: SetOptional<{a: number; b?: string; c: boolean}, 'b' | 'c'>;
expectNotAssignable<{a: boolean; b?: string; c?: boolean}>(variation4);