text: function createRangeValidator(minimum, maximum) {
    if (maximum < minimum) {
      throw new Error('Maximum is less than minimum');
    }
  
    return value => value >= minimum && value <= maximum;
  }
  
  function isBoolean(value) {
    return typeof value === 'boolean';
  }
  
  function createDiscreteOptionValidator(optionsArray) {
    if (!optionsArray || optionsArray.length === 0) {
      throw new Error('No options array, or it is empty.');
    }
  
    return value => optionsArray.indexOf(value) !== -1;
  }
  
  function isStringArray(stringArray) {
    return Array.isArray(stringArray) && stringArray.every(str => typeof str === typeof '');
  }
  
  function isMappable(value) {
    return !!value;
  }
  
  module.exports = {
    createRangeValidator,
    isBoolean,
    createDiscreteOptionValidator,
    isStringArray,
    isMappable,
  };
  