Functional programming

higher-order functions

None of these languages support Pure functions

Language/Paradigm	Tail recursion	folds	unfolds
JavaScript	❌	.reduce() method on arrays	❌
Python	❌	functools.reduce() function on iterables	❌
Typescript	❌	.reduce() method on arrays	❌
Java	❌	.reduce() method on streamable collections	❌
C#	❌	.Aggregate() method on collections	❌
C++	✅	std::accumulate on sequences.	❌
PHP	❌	array_reduce() on array	❌
Go	❌	❌	❌

They all support Product Types via Class, Record or Struct.

Language/Paradigm	Sum types	Pattern Matching	Dependent types
JavaScript	❌	❌	❌
Python	✅since 3.5 with typing.Union	✅since 3.10 with match statement	❌
Typescript	✅discriminated unions	switch-case with shared field.	some type-level computations
Java	Simulated via Sealed Interface	since Java 21	❌
C#	Simulated via Sealed Class	since C# 9.0	some type-level computations
C++	since C++17 with std::variant	since C++17 with std::visit	some type-level computations
PHP	❌	❌	❌
Go	❌	❌	❌