Remove Letter To Equalize Frequency

class CharCounter {
  private readonly map: Map<string, number>;
 
  constructor(str: string) {
    this.map = new Map();
    for (const char of str) {
      this.add(char);
    }
  }
 
  get(char: string): number {
    return this.map.get(char) ?? 0;
  }
 
  add(char: string) {
    return this.map.set(char, this.get(char) + 1);
  }
 
  sub(char: string) {
    return this.map.set(char, this.get(char) - 1);
  }
 
  delete(char: string) {
    return this.map.delete(char);
  }
 
  isSameCount() {
    return new Set(this.map.values()).size === 1;
  }
}
 
export function equalFrequency(word: string): boolean {
  const charCounter = new CharCounter(word);
 
  for (const char of word) {
    charCounter.sub(char);
    if (charCounter.get(char) === 0) {
      charCounter.delete(char);
    }
 
    if (charCounter.isSameCount()) {
      return true;
    }
 
    charCounter.add(char);
  }
 
  return false;
}