Tables are immensely better than JS objects, in every way. I could entertain a separate array type in the abstract, but given what actually exists, I will take tables over the JS collection of objects, arrays, and maps, any day.
Extensible syntax, which is used to implement "objects", but also to, well, extend the syntax. Indexing, assignment, calling a table like a function, operator overloading: it all works the same way, and it all works. Metatables are superior to prototype chains, simple as.
Coroutines. I don't have the energy to write up my personal take on why these are the best baseline abstraction for cooperative concurrency in a dynamic language; one of these days I'll publish something so I can simply link to it.
Multiple return values. A language without variadic parameters and multiple returns is less dynamic than one which has them, if you're going to go dynamic, go all in.
Environments! This is one of those things which you might not need very often, but when you do: oh man, great to have. Number one thing I would carry over into the browser, where we really don't want to leak context, and JS fights against this constantly.
As minor desiderata, Lua's type coercion, the fact that 0 is truthy, a separate `..` concatenation operator, and optional semicolons which basically cannot bite you: Lua has no need for a separate `==` and `===`, and I consider that a strength. I also think the separate `null` and `undefined` is clunky, but that opinion isn't strongly held; Lua has considered adding an `undef`, and it's an interesting debate which I'm just barely on the "no" side of.
Tables are immensely better than JS objects, in every way. I could entertain a separate array type in the abstract, but given what actually exists, I will take tables over the JS collection of objects, arrays, and maps, any day.
Extensible syntax, which is used to implement "objects", but also to, well, extend the syntax. Indexing, assignment, calling a table like a function, operator overloading: it all works the same way, and it all works. Metatables are superior to prototype chains, simple as.
Coroutines. I don't have the energy to write up my personal take on why these are the best baseline abstraction for cooperative concurrency in a dynamic language; one of these days I'll publish something so I can simply link to it.
Multiple return values. A language without variadic parameters and multiple returns is less dynamic than one which has them, if you're going to go dynamic, go all in.
Environments! This is one of those things which you might not need very often, but when you do: oh man, great to have. Number one thing I would carry over into the browser, where we really don't want to leak context, and JS fights against this constantly.
As minor desiderata, Lua's type coercion, the fact that 0 is truthy, a separate `..` concatenation operator, and optional semicolons which basically cannot bite you: Lua has no need for a separate `==` and `===`, and I consider that a strength. I also think the separate `null` and `undefined` is clunky, but that opinion isn't strongly held; Lua has considered adding an `undef`, and it's an interesting debate which I'm just barely on the "no" side of.