I’ve just completed my first survey of the current ECMAScript 4 implementations. I went through and attempted to compile as many bugs and features as possible, as stated by the ECMAScript 4 specification and double-check them against all the actively-maintained implementations. You can view a nice overview below.
I think it’s fascinating to note that there’s 3 implementations that already have over 25% of all the new features in the language implemented.
View: The raw data
About the implementations:
This is the reference implementation provided by the ECMA technical group, as a reference for those creating their own implementations.
Tamarin is the joint effort of Mozilla and Adobe to adapt the Open Source Adobe Virtual Machine to match ECMAScript 4 – and run in Firefox 3.next() (via ActionMonkey) and Flash 10.
Update from Tom:
Tamarin VM by itself doesn’t directly support ECMAScript source code. Rather, the subproject esc (written in ECMAScript 4) compiles ECMAScript 4 to abc bytecode that is run by the Tamarin VM.