Bridge · From syntax to engineering · 25 MIN

Preserve types while batching work

A generic can preserve the item type across a transformation.

A batcher should change grouping without losing the relationship between input and output items. T[] becomes T[][]: each item retains its type. slice copies the array segment so batching does not reorder or remove values from the source. An invalid size must be handled explicitly; a zero increment would otherwise make the loop infinite. These batches define groups only, not a concurrency guarantee. The consumer still decides whether groups run serially and how failures or cancellation propagate.

Write a small contract first, then test how the implementation behaves at its boundaries.

Read the example

const values: number[] = [1, 2, 3];
console.log(JSON.stringify(values.slice(0, 2)));

[1,2]

Your challenge

Input {items:JSON array,size:integer}. For size <= 0 return []; otherwise return consecutive groups of at most size items. Preserve order and leave the input unchanged.

Solution cost: O(n). time · O(n) for returned array slots; item objects are not deep copied. space

Common trap

splice changes the caller’s array; slice does not.

Further reading: TypeScript generics