No bug C:\Users\Alex\WebstormProjects\Tutorial01\Tests>tsc TS2.0.6NoBug.ts --target ES6 C:\Users\Alex\WebstormProjects\Tutorial01\Tests>tsc TS2.0.6Bug.ts --target ES6 TS2.0.6Bug.ts(28,21): error TS2322: Type 'void | IFoo[]' is not assignable to ty pe 'IFoo[]'. Type 'void' is not assignable to type 'IFoo[]'. C:\Users\Alex\WebstormProjects\Tutoria…

TS2.0.6NoBug.ts

interface IFoo{
    square:number
}
(
    async () => {

        async function squareFun(i:number) : Promise<IFoo>{
            if (i === 2)
                throw 'squareFun1 throw 2';
            return Promise.resolve({square: i * i});
        }


        async function getSquares3(): Promise<IFoo[]>{
            //I like this as I don't need to use Promise.all<IFoo>
            var squares = await Promise.all([squareFun(1), squareFun(4)]);
            return squares;
        }


        async function getSquares(): Promise<IFoo[]>{
            try {
                var promises = [1, 2, 3].map(n => squareFun(n));

                //var squares : Promise<IFoo[]> = Promise.all(promises);//type Promise<IFoo[]> not necessary, just added to verify that it is Promise<IFoo[]>
                var squares  = Promise.all(promises);
                //It can be compiled
                var cs : Promise<IFoo[]> = squares.catch(err => console.log('Catched error Promise.catch:' + err));

                //This cannot be compiled
                //var cs  = squares.catch(err => console.log('Catched error Promise.catch:' + err));
                var t : IFoo[] = await cs;
                return t;
            }
            catch(err){
                console.log('Catched error try/catch:' + err);
            }
        }


        var squares = await getSquares();
        if (squares)
            squares.forEach(s => console.log('square:' + s.square));

    }
)();