I just discovered Yuescript, which is like MoonScript with more features. I have mixed feelings.
I like features like pipelines (much cleaner than repeated assignment or nested parentheses in function calls) and compile-time macros. The sugar for multiple and destructuring assignment is handy.
I find the additional operators unnecessary, and not worth their cognitive overhead. It re-uses some operators for different purposes, creating confusion. The [] operator could easily have been a function in a library instead.
One of the trade-offs for this much syntactic sugar is some syntactic ambiguity. An opinionated formatter could resolve some of this.