var cars = ["mazda","honda","tesla"];
cars = []; // clear/empty the array
$foo = array(); // $foo is here again
unset($foo); // $foo is gone
A.length = 0
let arr = [3.14, 7];
arr = [];//make sure there is no other reference
var ar = [1, 2, 3, 4, 5, 6];
//do stuffar = [];
//a new, empty array!