Spread Operator

 // CLASS TOPICS : SPREAD OPERATORS  
   
   
 // we cannot sum two array like  
 // array1 = [1,2,3,4,5]  
 // array2 = [6,7,8]  
 // array3 = array1 + array2  
 // console.log(typeof(array3));  
 // we will get type string instead of a new array   
   
   
   
 // using spread opearators  
 // array1 = [1,2,3,4,5]  
 // array2 = [6,7,8]  
 // array3 = [...array1,...array2]  
 // console.log(array3)  
 // we can sum up two arrays [...] then array name like array1 and then again ...array2   
 // to sum up and get a new array with elements of both arrays  
   
   
   
 // using spread operator on object  
 // obj1 = {name:"shagun",age:23}  
 // obj2 = {gender:"male",name:"xyz"}  
 // obj3 = {...obj1,...obj2}  
 // console.log(obj3)  
 // here the only diff is that those properties which are same will get   
 //updated because we cannot have two key