Exercise 8: Generate Random String (alphanumeric)
Problem Statement
Create a function `randomString(length=8)` that generates a random alphanumeric string.
Example: randomString(6) → "a3B9x2"
Sample Output:
randomString(6) => "a3B9x2" (random) randomString(10) => "Xy7mN2pQ9k" (random) randomString(4) => "K9mP" (random)
Solution
const randomString = (length = 8) => {
const chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
return Array.from({ length }, () => chars[Math.floor(Math.random() * chars.length)]).join("");
};Explanation
Overall Goal:
- Random alphanumeric string generate karna (A-Z, a-z, 0-9).
- Specified length ka string return karna.
Line 1: Function header
const randomString = (length = 8) => {- Default length 8 characters.
Line 2: Character set
const chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";- All possible characters jo string me use honge.
Line 3: Generate string
Array.from({ length }, ...)→lengthsize ka array banata hai.() => chars[Math.floor(Math.random() * chars.length)]→ har position pe random character:Math.random()→ 0-1 ke beech random number.* chars.length→ 0-61 ke beech number.Math.floor(...)→ integer me convert.chars[index]→ random character pick..join("")→ array ko string me convert.
Real world:
- Password generation: temporary passwords.
- Token generation: API keys, session tokens.
- Unique IDs: short URLs, referral codes.