Interview Question: Given a text, return the most repeated letter.

index.js

'use strict';

/**
 * @function mostRepeatedLetter
 * @returns object the highest repeating letter and count
 *
 * @description
 *
 * Given a text: `I want to rock this interview`, return the most repeating letter.
 *
 * How it works:
 *
 * 1. Returns an object: highest repeating letter and its repeating count.
 * 2. Handle if `mostRepeaterLetter` receives empty text.
 * 3. TODO: What if two letters are repeating?
 * 4. TODO: Use `performance.now()` to measure and improve performance. See https://nodejs.org/api/perf_hooks.html#perf_hooks_performance_now
 */

function mostRepeatedLetter(text) {
  let arr = text.toLowerCase().match(/\p{L}/gu)
  console.log(arr.toString());

  let highestRepeatingCount = 0;
  let highestRepeatingLetter = null;

  for (let i = 0; i < arr.length; i++) {
    for (let j = 0; j < arr.length; j++) {

      console.log({
        '# of pass': i + 1,
        'arr[i]': arr[i],
        'arr[j]:': arr[j],
      });

      if (highestRepeatingCount === 0 && arr[i] === arr[j]) {
        highestRepeatingCount++;
        highestRepeatingLetter = arr[i];

        // cleanup
        arr[j] = '';

        // console.log({'i': `${i}`, 'j': `${j}`});
      } else if (highestRepeatingCount !== 0 && highestRepeatingLetter === arr[i] && arr[i] === arr[j]) {
        highestRepeatingCount++;
        highestRepeatingLetter = arr[i];

        // cleanup
        arr[j] = '';

        // console.log({'i': `${i}`, 'j': `${j}`});
      }
    }
  }

  return {
    count: highestRepeatingCount,
    letter: highestRepeatingLetter,
  };
}


const givenText = "I want to rock this interview";

const highestRepeating = mostRepeatedLetter(givenText);
console.log('Most repeated letter:', highestRepeating.letter);