Basic string compression

by Alex Myronov

JavaScript

const compress = (str) => {
	const arr = str.split('')

  let count = 0
  let result = ''

	for (let i = 0; i < arr.length; i++) {
  	count++
  	if (arr[i] !== arr[i + 1] || i + 1 >= arr.length) {
    	result = `${result}${arr[i]}${count}`
      count = 0
    }
  }
  
  return result
}

console.log(compress('aabccccaaa'))