Add the function range()

[rauschma]

Inspired by Python, it could be implemented as follows:

function* range(start=0, end=Infinity, step=1) {
    const posInc = step > 0;    
    while ((posInc && start < end) || (!posInc && start > end)) {
        yield start;
        start += step;
    }
}

[rauschma]

Alternatively:

function* range(start=0, end=Infinity, step=1) {
    if (step > 0) {
        while (start < end) {
            yield start;
            start += step;
        }
    } else {
        while (start > end) {
            yield start;
            start += step;
        }
    }
}

[fitzgen]

Advantages over count() and take? Convenience?

function* range(start=0, end=Infinity, step=1) {
    yield* count(start, step).take(end - start);
}

I'm not really against adding range, but also doesn't feel very compelling. Convince me?

[rauschma]

Oh my, I completely overlooked count()! Given count(), the case for range() is indeed not very strong.

Alas, I don’t see a way to add the parameter end to count() (without the order of parameters being weird). Main use case: using for-of to let a variable range over a series of values (something I needed to do recently).

for (let i of range(0, 3)) {
    console.log(i);
}

[fitzgen]

Agreed that adding an end parameter to count is iffy given the existing parameters and their order.

Is calling take explicitly onerous enough that this doesn't work?

for (let i of count(0).take(3)) {
    console.log(x);
}