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by.js
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by.js
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import iter from './iter.js';
import range from './range.js';
/**
* Yields elements of the input iterable by grouping them into tuples of a
* given size.
*
* @param {Iterable} iterable - The input iterable.
* @param {Number} n - The size of the yielded tuples.
* @returns {Iterator}
*/
export default function* by(iterable, n) {
const iterator = iter(iterable);
while (true) {
const tuple = [];
for (const i of range(n)) {
const current = iterator.next();
if (current.done) {
if (i === 0) {
return;
}
// eslint-disable-next-line no-unused-vars
for (const j of range(n - i)) {
tuple.push(undefined);
}
yield tuple;
return;
}
tuple.push(current.value);
}
yield tuple;
}
}