Comment by facepalm

Interesting - well I thought if it is being used by thousands of libraries it might be worth optimizing.

I just tried in NodeJS, you could also just instantiate an Array of a given length and join it with spaces, like this.

var x = new Array(5);x[4] = "abc";x.join(" ");

No idea if it could be faster - but the test you linked to pushes spaces into the Array.