ON Linear Time

TL;DR

O(n) linear time means cost grows in direct proportion to input size — double the data, double the work. It's the complexity of a single pass: map, filter, reduce, or one for loop over a collection. Linear is usually the practical target when you can't do better than touching every element once, and it's what you aim for when refactoring away an accidental O(n²).

How it works

const sum = (items: number[]) => items.reduce((acc, item) => acc + item, 0);

Notes

• Single passes through arrays are O(n).
• Filtering and mapping are O(n).