Post | mennovanslooten.nl/blog

A couple of months ago I wrote a little post about a trick to turn the built-in, array-like JavaScript variable arguments into an actual array that supports methods like slice, sort, etc. Today I found out that this little trick actually doesn't work in Apple's most popular browser: Safari. Here's a small addendum to that post.

The original trick was this:

var args = [].splice.call(arguments,0);

But unfortunately this doesn't work in Safari, the variable args just becomes an empty array. At first I thought the principle of calling an array method on arguments just didn't work but when a co-worker suggested trying the join() method that turned out to actually work. After a bit of experimenting I finally settled on the following snippet:

var args = [].slice.call(arguments,0);

Looks remarkably similar, doesn't it? The difference is just one letter: I call the slice method, in stead of the splice method. The slice method is very similar to splice in it's core functionality with one major difference: splice modifies the original array where slice doesn't. This, I believe is the problem for Safari when calling splice on arguments: this object is not modifiable. None of the other browsers seem to mind, though.