The best parts of Javascript are the practical ones:
- runs everywhere
- easy to deploy
- no worry about getting the right libraries
- good performance (thanks to really clever compilers)
- lots of tools and helpers
- easy to glue stuff together
- great for handling media
- easy to make stuff look good – use web infrastructure
- don’t need to worry about overall program structure
- debuggers and other tools
The basic ideas of the language are good
- Modern
- First class functions, lexical scope, closures
- prototype / delegation (rather than class/instance)
- memory managed
- Dictionary / Hash based data structures
- the dictionaries are queriable – allows for introspection
- Enables different ways of thinking (selector based like query)
- literals allow data in code (or code in data)
- Prototype/delegation-based (give flexibility)
Provides Mechanisms – programmers choose to use to make idioms
- fake classes
- chaining
- ducktyping
Lots of the details are wrong (in my opinion) – contrast with Python
- Lexically scoped – but only some times
- The confusion about this (invocation idioms)
- undefined is a valid value – generally,
- missing dictionary entries return undefined (not errors)
- too easy to do things globally (forget a var)
- too easy to re-write syntax
- too many things have too many ways to do them
- prototype is magic
- constructor functions are magic
- arguments array is not an array
Some things are just missing
- default parameters, keyword args
- decent support for lists
- nice iterators
- fast, fixed type arrays
- optional type checking
