javascript - Remove all items after an index

Question

I have an array:

array = ['mario','luigi','kong']

I call its splice function to remove all items before an index:

array.splice(1) //-> ['luigi','kong']

I'm just wondering if there is a function similar to splice to remove all items after an index:

pseudo code

array.mirrorsplice(1) //-> ['mario','luigi']

Answer 1

Use Array.length to set a new size for an array, which is faster than Array.splice to mutate:

var array = ['mario','luigi','kong', 1, 3, 6, 8];
array.length=2;
alert(array); // shows "mario,luigi";

Why is it faster? Because .splice has to create a new array containing all the removed items, whereas .length creates nothing and "returns" a number instead of a new array.

To address .splice usage, you can feed it a negative index, along with a huge number to chop off the end of an array:

var array = ['mario','luigi','kong'];
array.splice(-1, 9e9); 
alert(array); // shows "mario,luigi";