JSFiddle - React, Tailwind, and code Playground

by Allie Yu

JavaScript

const isPrime = num => {
  for(let i = 2; i < num; i++)
    if(num % i === 0) return false;
  return num > 1;
}
console.log(isPrime(37));

const countLetters = str => {
	let tempArr = str.split('');
  let letters = [];
  let count = 1;
  
  for (let i = 0; i < tempArr.length; i++) {
  	if (tempArr[i] === tempArr[i].toUpperCase()){
      if (tempArr[i] === tempArr[i+1]) {
        count++;
      } else {
        let value = `${tempArr[i]}${count}`;
        letters = [...letters, value];
        count = 1;
      }
    }
  }
  return letters.join('')
}
console.log(countLetters('AAAAAAaBBBIIKKK'))











/* function howManyRepeated(str){
  const result = [];
  const strArr = str.toLowerCase().split("").sort().join("").match(/(.)\1+/g);
  
  if (strArr != null) {
    strArr.forEach((elem) => {
      result.push(elem[0]);
    });
  }
  return result;
}
console.log(...howManyRepeated("aaaddd")); */



/* uniqueCount = ["a","b","c","d","d","e","a","b","c","f","g","h","h","h","e","a"];
var count = {};
uniqueCount.forEach(function(i) { count[i] = (count[i]||0) + 1;});
console.log(count); */