Coffeescript had some great features: classes, array comprehensions, default parameter values, arrow functions, optional chaining. Many of these eventually made it to ecmascript.
And then it ruined us with implicit returns, optional parentheses and brackets, and the isnt vs is not fiasco.
I worked a lot with Python and coffeescript at the same time back in the day. In Python you mess up your whitespace and 95% of the time it's an indentation error. In coffeescript it's a valid program that means something completely different than what you intended. Combined with the optional punctuation, which the community encouraged leaning into, it was far too easy to write ambiguous code that you and the compiler would come to different interpretations of.
In case you wondered how Civet compared to CoffeeScript in these regards:
* `is not` is the textual equivalent of `!==`. You can use `isnt` if you turn on the feature explicitly (or even the weird CoffeeScript `is not` behavior if you want it, mainly for legacy code)
* Implicit returns are turned on by default. They are really useful, most of the time, and don't get in the way much if you use `void` return annotations (which turns them off). But if you don't like them, you can turn them off globally with a compiler flag.
* Civet's compiler is built on very different technology from CoffeeScript's (PEG parsing, similar to Python), and it is much more strict about indentation. None of those weird bugs anymore.
* We do have implicit parentheses and braces and such, but you're free to use explicit parentheses and braces as you like. We encourage people to rename their .ts files into .civet (which mostly just works without any converison) and just embrace the features/syntax they like.
And then it ruined us with implicit returns, optional parentheses and brackets, and the isnt vs is not fiasco.
I worked a lot with Python and coffeescript at the same time back in the day. In Python you mess up your whitespace and 95% of the time it's an indentation error. In coffeescript it's a valid program that means something completely different than what you intended. Combined with the optional punctuation, which the community encouraged leaning into, it was far too easy to write ambiguous code that you and the compiler would come to different interpretations of.