Composability in JavaScript refers to the ability to combine smaller, reusable functions, components, or modules to build more complex and larger functionalities. It allows developers to write cleaner, more maintainable, and modular code.

In functional programming emphasizes composing functions to create more complex behaviors.

Key concepts include:

Higher-order functions: Functions that take other functions as arguments or return them.

Pure functions: Functions that have no side effects and return the same output given the same input.

Function composition: Combining two or more functions to produce a new function.