how to call class function in javascript code example

Example: javascript call class method

'use strict' 
class Polygon { 
   constructor(height, width) { 
      this.h = height; 
      this.w = width;
   } 
   test() { 
      console.log("The height of the polygon: ", this.h) 
      console.log("The width of the polygon: ",this. w) 
   } 
} 

//creating an instance  
var polyObj = new Polygon(10,20); 
polyObj.test();