Heterogenous arrays can have very poor performance on some JavaScript VMs, particularly Google's V8. If you can avoid them in performance sensitive code, it's a

Heterogenous arrays can have very poor performance on some JavaScript VMs, particularly Google's V8. If you can avoid them in performance sensitive code, it's a good idea to do so. For more information, see this excellent talk: http://v8-io12.appspot.com/ http://v8-io12.appspot.com/