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// @strict: true
// from https://github.com/microsoft/TypeScript/issues/30717
declare class Test<T> {
obj: T;
get<K extends keyof T>(k: K): T[K];
}
interface A { t: "A" }
interface B { t: "B" }
declare const tmp: Test<A> | Test<B>;
switch (tmp.get('t')) {
case 'A': break;
case 'B': break;
}
// from https://github.com/microsoft/TypeScript/issues/36390
const arr: number[] | string[] = []; // Works with Array<number | string>
const arr1: number[] = [];
const arr2: string[] = [];
arr.map((a: number | string, index: number) => {
return index
})
// This case still doesn't work because `reduce` has multiple overloads :(
arr.reduce((acc: Array<string>, a: number | string, index: number) => {
return []
}, [])
arr.forEach((a: number | string, index: number) => {
return index
})
arr1.map((a: number, index: number) => {
return index
})
arr1.reduce((acc: number[], a: number, index: number) => {
return [a]
}, [])
arr1.forEach((a: number, index: number) => {
return index
})
arr2.map((a: string, index: number) => {
return index
})
arr2.reduce((acc: string[], a: string, index: number) => {
return []
}, [])
arr2.forEach((a: string, index: number) => {
return index
})
// from https://github.com/microsoft/TypeScript/issues/36307
declare class Foo {
doThing(): Promise<this>
}
declare class Bar extends Foo {
bar: number;
}
declare class Baz extends Foo {
baz: number;
}
declare var a: Bar | Baz;
// note, you must annotate `result` for now
a.doThing().then((result: Bar | Baz) => {
// whatever
});
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