How to find total count of consecutive repeated characters and numbers in a string using javascript?

Question

I want to get total count of consecutive repeated characters and numbers in a string. For example : const value = '11111aaaio222' So the output should be 11

Explanation:

"1" repeating 5 times

"a" repeating 3 times

"2" repeating 3 times

Answer 1

You can achieve it using a simple regex as well. Following regex matches 2 or more consecutive repeated characters.

/(.)\1+/g

• (.) - match any character
• \1+ - match the previously matched character again one or more times

const regexp = /(.)\1+/g;
const str = '11111aaaio222';

const output = str.match(regexp).join('').length;

console.log(output)

Answer 2

const data = "11111aaaio222";

const result = Array.from(new Set([...data])).reduce((p, c) => {
    let tc = 0;
    [...data].forEach((ta, i) => {
        if (ta === c && data[i + 1] === c) tc++;
    })
    tc && (p += tc + 1);
    return p;
}, 0)

console.log(result);

Answer 3

To calculate the number of repetitions you can use regex:

([a-zA-Z\d])\1*

It will return groups of values like this [11111, aaa, i, o, 222].

Now we need to go through the array with reduce and calculate the number of repeating elements. We also need to remove elements that are less than 2

const count = (str) => {
  const regex = /([a-zA-Z\d])\1*/g;
  const matches = str.match(regex) || [];
  return matches.reduce((acc, item) => {
    acc += item.length > 1 ? item.length : 0;
    return acc
  }, 0);
}

console.log(count("11111aaaio222"))

So we go through the array and sum up only those values that are repeated more than once.

current value: 0, item - 11111
current value: 5, item - aaa
current value: 8, item - i
current value: 8, item - o
current value: 8, item - 222
output value: 11

Answer 4

function duplicateCharCount(str) {
    if(str) {
        var obj = {};
        for(let i = 0; i < str.length; i++) {
            if(obj[str[i]]){
                obj[str[i]] += obj[str[i]];
            }else {
                obj[str[i]] = 1;
            }
        }
        console.log(obj);
    }
            
}

duplicateCharCount("aabcdd");

https://gist.github.com/msaxena25/62d17a1c9b1e507f2eafd83fc7d54db0