text: function stringLength(string) {
    if (string.length > 10 || string.length < 1) {
      throw new Error('too long or too short');
    }
    return string.length;
  }
  
  function reverseString(string) {
    return string.split('').reverse().join('');
  }
  
  class Calc {
    constructor(a = 0, b = 0) {
      this.a = a;
      this.b = b;
    }
  
    add() {
      return this.a + this.b;
    }
  
    subtract() {
      return this.a - this.b;
    }
  
    divide() {
      return this.a / this.b;
    }
  
    multiply() {
      return this.a * this.b;
    }
  }
  
  function capitalizeString(string) {
    return string[0].toUpperCase() + string.slice(1);
  }
  
  export {
    stringLength, reverseString, Calc, capitalizeString,
  };