Compute how is the frequency of each char in a string. Returns a Map.

computeFrequency.ts

function computeFrequency(input: string): Map<string, number> {
  const freqTable = new Map();
  for (let ch of input) {
    if (!freqTable.has(ch)) {
      freqTable.set(ch, 1);
    } else {
      freqTable.set(ch, freqTable.get(ch) + 1);
    }
  }

  return freqTable;
}
  
  console.log(computeFrequency("12345")); // Map (5) {"1" => 1, "2" => 1, "3" => 1, "4" => 1, "5" => 1}