text: class StringBuilder {
    constructor(value) {
      this._value = value;
    }
    get value() {
      return this._value;
    }
    append(str) {
      this._value = this._value + str;
    }
    prepend(str) {
      this._value = str + this._value;
    }
    pad(str) {
      this._value = str + this._value + str;
    }
  }
  
  const builder = new StringBuilder(".");
  
  builder.append("^");
  console.log(builder.value);
  
  builder.prepend("^");
  console.log(builder.value);
  
  builder.pad("=");
  console.log(builder.value);
  