问如何在for循环中创建的Promise之后使用Promise.all()

EN

var foo = (x) => {
    var arr = [];
    for (var i = 0; i < 100; i++) {
        arr.push(someOtherFunctionThatReturnsAPromise(x).then(returnSomething));
    }
    return arr
};

function nowDoEverything() {
    return Promise.all([...foo(1), ...foo(2), ...foo(3)])
           .then(doSomethingWithAllThoseReturnedValues)
}

nowDoEverything()
.catch(err => console.log(err));

Promise.all<T>: (Iterable<Promise<T>): Promise<T[]>

var foo = x => {
    var results = [];

    for (var i = 0; i < 100; i++) {
        results.push(
            someOtherFunctionThatReturnsAPromise(x)
                .then(returnSomething)
        );
    }

    return Promise.all(results);
};