Sort an Array in JavaScript: Numeric Order and Tie Breakers

The task

Order inspection jobs by ascending duration, then by numeric job ID when durations tie. Keep a separate short number list to expose what default sorting does.

Runnable Node 22 example

const assert = require('node:assert/strict');

const lexical = [12, 3, 20];
lexical.sort();
assert.deepEqual(lexical, [12, 20, 3]);
const jobs = [{id: 8, minutes: 15}, {id: 2, minutes: 5}, {id: 4, minutes: 15}];
const returned = jobs.sort((a, b) => a.minutes - b.minutes || a.id - b.id);
assert.equal(returned, jobs);
assert.deepEqual(jobs.map(job => job.id), [2, 4, 8]);
console.log(JSON.stringify(jobs.map(job => job.id)));

Expected output and explanation

The default example places 20 before 3 because it is not applying numeric magnitude. The record comparator first compares minutes; a zero difference falls through to the ID comparison. That makes the required tie policy explicit rather than dependent on input order.

The identity assertion shows that sort returns the same array it rearranges. The record values are not rewritten, but their positions change. Call toSorted when you specifically need a new sorted container in a supporting runtime, or choose another deliberate nonmutating approach.

Pitfall to check

A comparator should return a negative, zero or positive number consistently. Returning only true or false fails to describe both directions. Define a policy for missing or invalid durations before sorting; this fixture contains finite numbers only.