const test = "ABCCABC";

let countSubstrings = ((input, length) => {
  let countMap = new Map();
  for(let i = 0; i < input.length - (length - 1); i++){
    const window = input.slice(i, i + length);
    if(countMap.has(window)){
      countMap.set(window, countMap.get(window) + 1);
    }
    else{
      countMap.set(window, 1);
    }
  }
  for([key, count] of countMap){
    console.log(key + ": " + count);
  }
});

for(let i = 1; i <= test.length; i ++){
  countSubstrings(test, i);
}