asyncFunctionReturnType.js

//// [asyncFunctionReturnType.ts]
async function fAsync() {
    // Without explicit type annotation, this is just an array.
    return [1, true];
}

async function fAsyncExplicit(): Promise<[number, boolean]> {
    // This is contextually typed as a tuple.
    return [1, true];
}

// https://github.com/Microsoft/TypeScript/issues/13128
interface Obj {
    stringProp: string;
    anyProp: any;
}

async function fIndexedTypeForStringProp(obj: Obj): Promise<Obj["stringProp"]> {
    return obj.stringProp;
}

async function fIndexedTypeForPromiseOfStringProp(obj: Obj): Promise<Obj["stringProp"]> {
    return Promise.resolve(obj.stringProp);
}

async function fIndexedTypeForExplicitPromiseOfStringProp(obj: Obj): Promise<Obj["stringProp"]> {
    return Promise.resolve<Obj["stringProp"]>(obj.stringProp);
}

async function fIndexedTypeForAnyProp(obj: Obj): Promise<Obj["anyProp"]> {
    return obj.anyProp;
}

async function fIndexedTypeForPromiseOfAnyProp(obj: Obj): Promise<Obj["anyProp"]> {
    return Promise.resolve(obj.anyProp);
}

async function fIndexedTypeForExplicitPromiseOfAnyProp(obj: Obj): Promise<Obj["anyProp"]> {
    return Promise.resolve<Obj["anyProp"]>(obj.anyProp);
}

async function fGenericIndexedTypeForStringProp<TObj extends Obj>(obj: TObj): Promise<TObj["stringProp"]> {
    return obj.stringProp;
}

async function fGenericIndexedTypeForPromiseOfStringProp<TObj extends Obj>(obj: TObj): Promise<TObj["stringProp"]> {
    return Promise.resolve(obj.stringProp);
}

async function fGenericIndexedTypeForExplicitPromiseOfStringProp<TObj extends Obj>(obj: TObj): Promise<TObj["stringProp"]> {
    return Promise.resolve<TObj["stringProp"]>(obj.stringProp);
}

async function fGenericIndexedTypeForAnyProp<TObj extends Obj>(obj: TObj): Promise<TObj["anyProp"]> {
    return obj.anyProp;
}

async function fGenericIndexedTypeForPromiseOfAnyProp<TObj extends Obj>(obj: TObj): Promise<TObj["anyProp"]> {
    return Promise.resolve(obj.anyProp);
}

async function fGenericIndexedTypeForExplicitPromiseOfAnyProp<TObj extends Obj>(obj: TObj): Promise<TObj["anyProp"]> {
    return Promise.resolve<TObj["anyProp"]>(obj.anyProp);
}

async function fGenericIndexedTypeForKProp<TObj extends Obj, K extends keyof TObj>(obj: TObj, key: K): Promise<TObj[K]> {
    return obj[key];
}

async function fGenericIndexedTypeForPromiseOfKProp<TObj extends Obj, K extends keyof TObj>(obj: TObj, key: K): Promise<TObj[K] extends PromiseLike<infer U> ? U : TObj[K]> {
    return Promise.resolve(obj[key]);
}

async function fGenericIndexedTypeForExplicitPromiseOfKProp<TObj extends Obj, K extends keyof TObj>(obj: TObj, key: K): Promise<TObj[K] extends PromiseLike<infer U> ? U : TObj[K]> {
    return Promise.resolve<TObj[K]>(obj[key]);
}


//// [asyncFunctionReturnType.js]
var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
    return new (P || (P = Promise))(function (resolve, reject) {
        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
        step((generator = generator.apply(thisArg, _arguments || [])).next());
    });
};
function fAsync() {
    return __awaiter(this, void 0, void 0, function* () {
        // Without explicit type annotation, this is just an array.
        return [1, true];
    });
}
function fAsyncExplicit() {
    return __awaiter(this, void 0, void 0, function* () {
        // This is contextually typed as a tuple.
        return [1, true];
    });
}
function fIndexedTypeForStringProp(obj) {
    return __awaiter(this, void 0, void 0, function* () {
        return obj.stringProp;
    });
}
function fIndexedTypeForPromiseOfStringProp(obj) {
    return __awaiter(this, void 0, void 0, function* () {
        return Promise.resolve(obj.stringProp);
    });
}
function fIndexedTypeForExplicitPromiseOfStringProp(obj) {
    return __awaiter(this, void 0, void 0, function* () {
        return Promise.resolve(obj.stringProp);
    });
}
function fIndexedTypeForAnyProp(obj) {
    return __awaiter(this, void 0, void 0, function* () {
        return obj.anyProp;
    });
}
function fIndexedTypeForPromiseOfAnyProp(obj) {
    return __awaiter(this, void 0, void 0, function* () {
        return Promise.resolve(obj.anyProp);
    });
}
function fIndexedTypeForExplicitPromiseOfAnyProp(obj) {
    return __awaiter(this, void 0, void 0, function* () {
        return Promise.resolve(obj.anyProp);
    });
}
function fGenericIndexedTypeForStringProp(obj) {
    return __awaiter(this, void 0, void 0, function* () {
        return obj.stringProp;
    });
}
function fGenericIndexedTypeForPromiseOfStringProp(obj) {
    return __awaiter(this, void 0, void 0, function* () {
        return Promise.resolve(obj.stringProp);
    });
}
function fGenericIndexedTypeForExplicitPromiseOfStringProp(obj) {
    return __awaiter(this, void 0, void 0, function* () {
        return Promise.resolve(obj.stringProp);
    });
}
function fGenericIndexedTypeForAnyProp(obj) {
    return __awaiter(this, void 0, void 0, function* () {
        return obj.anyProp;
    });
}
function fGenericIndexedTypeForPromiseOfAnyProp(obj) {
    return __awaiter(this, void 0, void 0, function* () {
        return Promise.resolve(obj.anyProp);
    });
}
function fGenericIndexedTypeForExplicitPromiseOfAnyProp(obj) {
    return __awaiter(this, void 0, void 0, function* () {
        return Promise.resolve(obj.anyProp);
    });
}
function fGenericIndexedTypeForKProp(obj, key) {
    return __awaiter(this, void 0, void 0, function* () {
        return obj[key];
    });
}
function fGenericIndexedTypeForPromiseOfKProp(obj, key) {
    return __awaiter(this, void 0, void 0, function* () {
        return Promise.resolve(obj[key]);
    });
}
function fGenericIndexedTypeForExplicitPromiseOfKProp(obj, key) {
    return __awaiter(this, void 0, void 0, function* () {
        return Promise.resolve(obj[key]);
    });
}