Iterator.prototype.chunks()
The chunks() method of Iterator instances returns a new iterator helper object that yields non-overlapping element sequences as arrays. Each time, the specified number of elements are retrieved from the underlying iterator and are yielded together as a chunk.
For yielding overlapping sequences (i.e., sliding window), see Iterator.prototype.windows().
Syntax
chunks(chunkSize)
Parameters
chunkSize-
The number of elements in each chunk. Must be a positive integer less than 232 (the maximum array length).
Return value
A new iterator helper object. Each time the returned iterator helper's next() method is called, the current iterator is advanced by chunkSize elements, and those elements are yielded together as an array.
If the current iterator has some but fewer than chunkSize elements remaining, those elements are still yielded as an array (so the length is less than chunkSize), and the iterator helper will be immediately completed the next time next() is called.
If the current iterator has no elements remaining, the iterator helper is immediately completed without yielding an empty array.
Exceptions
TypeError-
Thrown if
chunkSizeis not an integer. RangeError-
Thrown if
chunkSizeis less than 1 or greater than 232－1.
Examples
Printing elements in a grid
The following example creates an iterator that yields terms in the Fibonacci sequence. Then, they are printed in a grid layout by retrieving 5 elements each time.
function* fibonacci() {
let current = 1;
let next = 1;
while (true) {
yield current;
[current, next] = [next, current + next];
}
}
const rows = fibonacci().chunks(5);
for (const row of rows.take(5)) {
console.log(row.join("\t"));
}
Output:
1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 1597 2584 4181 6765 10946 17711 28657 46368 75025
Specifications
| Specification |
|---|
| Iterator Chunking # sec-iterator.prototype.chunks |