Assembly, C, Javascript and Java are equally "expressive" in the sense that they're Turing complete. Anything that can be "expressed" in Javascript can be "expressed" in Assembly.
Most of the features people like in Javascript can be faked in some manner in Java. Anonymous objects can be used to insert anonymous functions into Java code... At great cost in verbosity. Variables never really escape Java "closures" but the resulting immutability leads to a functional programming style that has real benefits.
Javascript's real advantage is a clearer syntax that's easier to learn and easier to read. If statically typed languages value concision, we can get the benefits of static types with little cost.
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Assembly, C, Javascript and Java are equally "expressive" in the sense that they're Turing complete. Anything that can be "expressed" in Javascript can be "expressed" in Assembly.
Most of the features people like in Javascript can be faked in some manner in Java. Anonymous objects can be used to insert anonymous functions into Java code... At great cost in verbosity. Variables never really escape Java "closures" but the resulting immutability leads to a functional programming style that has real benefits.
Javascript's real advantage is a clearer syntax that's easier to learn and easier to read. If statically typed languages value concision, we can get the benefits of static types with little cost.
Expressiveness of a language is not the scope of what it can express, but how much you must write in order to express something.