1---
2title: Use Loop for Min/Max Instead of Sort
3impact: LOW
4impactDescription: O(n) instead of O(n log n)
5tags: javascript, arrays, performance, sorting, algorithms
6---
7 
8## Use Loop for Min/Max Instead of Sort
9 
10Finding the smallest or largest element only requires a single pass through the array. Sorting is wasteful and slower.
11 
12**Incorrect (O(n log n) - sort to find latest):**
13 
14```typescript
15interface Project {
16  id: string
17  name: string
18  updatedAt: number
19}
20 
21function getLatestProject(projects: Project[]) {
22  const sorted = [...projects].sort((a, b) => b.updatedAt - a.updatedAt)
23  return sorted[0]
24}
25```
26 
27Sorts the entire array just to find the maximum value.
28 
29**Incorrect (O(n log n) - sort for oldest and newest):**
30 
31```typescript
32function getOldestAndNewest(projects: Project[]) {
33  const sorted = [...projects].sort((a, b) => a.updatedAt - b.updatedAt)
34  return { oldest: sorted[0], newest: sorted[sorted.length - 1] }
35}
36```
37 
38Still sorts unnecessarily when only min/max are needed.
39 
40**Correct (O(n) - single loop):**
41 
42```typescript
43function getLatestProject(projects: Project[]) {
44  if (projects.length === 0) return null
45  
46  let latest = projects[0]
47  
48  for (let i = 1; i < projects.length; i++) {
49    if (projects[i].updatedAt > latest.updatedAt) {
50      latest = projects[i]
51    }
52  }
53  
54  return latest
55}
56 
57function getOldestAndNewest(projects: Project[]) {
58  if (projects.length === 0) return { oldest: null, newest: null }
59  
60  let oldest = projects[0]
61  let newest = projects[0]
62  
63  for (let i = 1; i < projects.length; i++) {
64    if (projects[i].updatedAt < oldest.updatedAt) oldest = projects[i]
65    if (projects[i].updatedAt > newest.updatedAt) newest = projects[i]
66  }
67  
68  return { oldest, newest }
69}
70```
71 
72Single pass through the array, no copying, no sorting.
73 
74**Alternative (Math.min/Math.max for small arrays):**
75 
76```typescript
77const numbers = [5, 2, 8, 1, 9]
78const min = Math.min(...numbers)
79const max = Math.max(...numbers)
80```
81 
82This works for small arrays, but can be slower or just throw an error for very large arrays due to spread operator limitations. Maximal array length is approximately 124000 in Chrome 143 and 638000 in Safari 18; exact numbers may vary - see [the fiddle](https://jsfiddle.net/qw1jabsx/4/). Use the loop approach for reliability.
83