This is one of the fastest if not THEE fastest way to empty an array. With this technique you won't need to create a new array, it will let you reuse the same exact array:
Var myArray = ["one", "two", "three"];
// console.log( myArray ) => ["one", "two", "three"]
myArray.length = 0;
// console.log( myArray ) => []
Var myArray = ["one", "two", "three"];
// console.log( myArray ) => ["one", "two", "three"]
myArray.length = 0;
// console.log( myArray ) => []