> Strings in Lua are interned, which makes it possible to efficiently use string keys in all sorts of places instead of numeric enumerations. Interning is an i

> Strings in Lua are interned, which makes it possible to efficiently use string keys in all sorts of places instead of numeric enumerations. Interning is an implementation detail. I don't know how they are implemented off the top of my head, but string keys are pretty damn fast in most JS JITs, since they're used to get e.g. methods of objects. > Lua's garbage collector has support for running incrementally with a configurable pause time, so you can run it in the background every frame to avoid those nasty GC pauses you still get in most modern browser games from stop-the-world collections. Again, this is an implementation detail. Firefox is about to get incremental GC. While the pause time isn't configurable, it doesn't really matter as long as it's short by default. > Debugging is built into the language with a user-accessible API that lets you write your own debugger or diagnostic tool, in addition to using third-party ones, instead of having to rely on the vendor to provide one. Gecko and WebKit both have debugging APIs. I will concede that it's a PITA that they're different. > Lua uses a single container type for storing data, with an efficient representation (densely packed elements are stored in an actual array; sparsely packed elements and elements with non-integral keys are stored in a hashmap). As a result, operations on sequences/containers only ever have to think about one data type, and you still get the near-optimal performance you would in JS if you manually used Array/Object where most appropriate. Again, this is an implementation detail. In JS, Array is a subclass of Object and in most JITs I think it's implemented the same way. The only difference is how they serialize to JSON and that Array has a length property. Lua has an advantage in that it gives arrays both sparse and dense slots, but this isn't necessarily impossible to do in JS either (https://bugzilla.mozilla.org/show_bug.cgi?id=586842 https://bugzilla.mozilla.org/show_bug.cgi?id=586842)