Generate random alpha-numeric string in JavaScript

In this article with the help of javascript  we are generating the alpha-numeric string of specific length using javascript, here are some common method 

Approach 1:

• Creates a function that takes 2 arguments one is the length of the string that we want to generate and another is the characters that we want to be present in the string.
• Declare new variable ans = ‘ ‘.
• Traverse the string in reverse order using for loop.
• Use JavaScript Math.random() method to generate the random index and multiple with the length of the string.
• Use JavaScript Math.floor( ) to round off it and add it into the ans.

Example 1: This example uses the Math.random() method to generate the random index and then appends the character from the string we passed. 

Javascript

function randomStr(len, arr) {
    let ans = '';
    for (let i = len; i > 0; i--) {
        ans +=
            arr[(Math.floor(Math.random() * arr.length))];
    }
    console.log(ans);
}

randomStr(20, '12345abcde');

Output

eecedee32d5245ba5ee3

Approach 2:

• First, generate a random number using Math.random() method.
• Use JavaScript toString(36) to convert it into base 36 (26 char + 0 to 9) which is also an alpha-numeric string.
• Use JavaScript String.slice() method to get the part of the string which is started from position 2.

Example 2: This example first generates a random number(0-1) and then converts it to base 36 which is also an alpha-numeric string by using toString(36)() method. 

Javascript

function GFG_Fun() {
    console.log(
        Math.random().toString(36).slice(2));
}
GFG_Fun()

Output

vv1lcnuwtm