String Compression

String Compression

Write a method that takes a string as input and returns a compressed version of it, as shown in the example below:

Input: aaabbddd

Output: a3b2d3

Video Link: https://youtu.be/PuoTbJydRiA

Program: 

/*

String can also contain single characters 

For example : ab

then the output would be : ab and not a1b1

*/

process.stdin.setEncoding('utf-8');

console.log('Enter a series of characters to compress. 1 to quit');

process.stdin.on('data', (data) => {

    if (data == '1\n') {

        process.exit();

    }

    if (!isNaN(data)) {

        console.log('Please enter characters only');

        process.exit();

    }

    let str = data;

    let count = 1; // to check the number of repeated characters

    let strCopy = '' // to store output

    for (let index = 0; index < str.length; index++) {

        // if characters are uppercase then we have to compare then using toLowercase function

        if (str[index].toLowerCase() == str[index + 1] && str[index + 1].toLowerCase()) {

            count++;

        } else {

            strCopy += count > 1 ? str[index] + count : str[index];

            count = 1; // reset the count

        }

    }

    // Print the result string

    console.log(strCopy);

})