Axel Rauschmayer wrote:
AFAICT, `return()` throwing an exception (versus performing a `return`) is
necessary
It's not necessary, it just might be a bit more complicated:
function* take(n, iterable) {
let iterator = iterable[Symbol.iterator]();
n = +n; // make sure it's a number, so that n>0 does never throw
try {
while (n > 0) {
let item = iterator.next();
if (item.done) {
return item.value;
}
yield item.value;
n--;
}
} catch (e) {
iterator.throw(e);
} finally {
iterator.return();
}
}
(I assume calling `throw` or `return` on a finished iterator is simply
ignored, I'll have to check this back with the spec).
The above code also has the additional nice property that it call
`.return()` on the iterator when `n` values have been taken out of it.
Bergi
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