how to define class variable in javascript code example

Example 1: javascript classes

//use classes by initiating one like so:
class MyClass {
	constructor(FirstProperty, SecondProperty, etcetera) {
    	//The constructor function is called with the new class 
      	//instance's parameters, so this will be called like so:
      	//var classExample = new MyClass("FirstProperty's Value", ...)
      this.firstProperty = FirstProperty;
      this.secondProperty = SecondProperty;
    }
  //creat methods just like functions:
  method(Parameters) {
  	//Code Here
  }
  //getters are properties that are calculated when called, versus fixed
  //variables, but still have no parenthesis when used
  get getBothValues() 
  {
  	return [firstProperty, secondProperty];
  }
}
//Note: this is all syntax sugar reducing the boilerplate versus a
// function-defined object.

Example 2: javascript create class

class Car {
  constructor(brand) {
    this.carname = brand;
  }
}