Sort by

83.2% acceptance

Mar 2, 2026

228

Given an array arr and a function fn, return a sorted array sortedArr. You can assume fn only returns numbers and those numbers determine the sort order of sortedArr. sortedArr must be sorted in ascending order by fn output. You may assume that fn will never duplicate numbers for a given array.

Solution

TypeScript

Time O(n log n)

Space O(1)

LeetCode

solution.ts

type JSONValue =
  | null
  | boolean
  | number
  | string
  | JSONValue[]
  | { [key: string]: JSONValue };
type Fn = (value: JSONValue) => number;

function sortBy(arr: JSONValue[], fn: Fn): JSONValue[] {
  return [...arr].sort((a, b) => fn(a) - fn(b));
}