Iterator chunking

Overlapping/non-overlapping streams of configurable size.

Type	TC39	CoreJS	Babel	Civet	JS+
Polyfill	✅ Stage 2.7 View	✅ View	❌	❌	✅ via Custom

Iterator.prototype.chunks<T>(chunkSize: number): [T[]]

Baseline

Splits the iterator into non-overlapping arrays of length chunkSize. If the iterator’s length is not evenly divisible, the final chunk contains the remaining elements.

[...[1, 2, 3, 4, 5].values().chunks(2)]
// → [[1, 2], [3, 4], [5]]

[...[1, 2, 3].values().chunks(3)]
// → [[1, 2, 3]]

[...[1, 2, 3].values().chunks(5)]
// → [[1, 2, 3]]

Iterator.prototype.windows<T>(windowSize: number, undersized?: 'allow-partial'): [T[]]

Baseline

Produces a sliding window over the iterator, yielding overlapping arrays of length windowSize. Each step advances by one element.

[...[1, 2, 3, 4, 5].values().windows(3)]
// → [[1, 2, 3], [2, 3, 4], [3, 4, 5]]

[...[1, 2, 3, 4].values().windows(3, "allow-partial")]
// → [[1, 2, 3], [2, 3, 4], [3, 4], [4]]

// Iterator shorter than windowSize — "only-full" yields nothing
[...[1, 2].values().windows(3)]
// → []

// Iterator shorter than windowSize — "allow-partial" yields what's there
[...[1, 2].values().windows(3, "allow-partial")]
// → [[1, 2]]