How to empty an Array in JavaScript?

It's very simply but hard to empty an Array using Javascript.

There are 4 ways to achieve this task.
For Example:-

We make a function:-

function empty_array()
{   
   //1st way
   var array_val1 = [1,2,3,4];
   array_val1 = [];
   
   //2nd way
   var array_val2 = [1,2,3,4];
   array_val2.splice(0,array_val2.length);
   
   //3rd way
   var array_val3 = [1,2,3,4];
   array_val3.length = 0;
   
   //4th way
   var array_val4 = [1,2,3,4];
   array_val4 = new Array();

   alert(array_val1);
   alert(array_val2);
   alert(array_val3);
   alert(array_val4);
}

Explaination:-
1). array_val1 = [] -> Meaning,we are creating new object or array.
2). array_val3.length = 0 -> Assigning array'length to 0.
3). array_val4 = new Array(); -> Same as 1 option.