Exercise 19: Find Maximum Number in Array
Problem Statement
Create a function `findMax(arr)` that finds the maximum number in an array. Return null for empty array.
Example: findMax([3, 7, 2, 9, 1]) → 9
Sample Output:
findMax([3, 7, 2, 9, 1]) => 9 findMax([-5, -2, -10]) => -2 findMax([]) => null
Solution
const findMax = (arr) => {
if (!Array.isArray(arr) || arr.length === 0) return null;
return Math.max(...arr.filter(n => typeof n === "number" && Number.isFinite(n)));
};Explanation
Overall Goal:
- Array me se maximum number find karna.
- Invalid values ignore karna.
Line 1: Function header
const findMax = (arr) => {
Line 2: Validation
if (!Array.isArray(arr) || arr.length === 0) return null;- Not array ya empty ho to null.
Line 3: Find max
return Math.max(...arr.filter(...));- Filter valid numbers, phir Math.max.
Real world:
- Analytics: highest values.
- Leaderboards: top scores.
- Data analysis: maximum values.