Question

I have two arrays: ArrayA and ArrayB. I need to copy ArrayA into ArrayB (as opposed to create a reference) and I’ve been using .splice(0) but I noticed that it seems to removes the elements from the initial array.

In the console, when I run this code:

var ArrayA = [];
var ArrayB = [];

ArrayA.push(1);
ArrayA.push(2);

ArrayB = ArrayA.splice(0);

alert(ArrayA.length);

the alert shows 0. What am I doing wrong with .splice(0)??

Thanks for your insight.

Answer 1

You want to use slice() (MDN docu) and not splice() (MDN docu)!

ArrayB = ArrayA.slice(0);

slice() leaves the original array untouched and just creates a copy.

splice() on the other hand just modifies the original array by inserting or deleting elements.