What are closures in JavaScript?

Closures are a powerful feature in JavaScript that allows functions to retain access to variables from their containing scope even after that scope has closed. This capability is fundamental to many common design patterns in JavaScript and is leveraged in various frameworks and libraries.

How do closures work?

In JavaScript, functions can be defined within other functions, creating what is known as nested functions. These inner functions have access to their containing (outer) function's scope, as well as the global scope. When an inner function captures and retains access to variables from its outer function, even after the outer function has completed execution, a closure is formed.

Benefits of closures

Closures allow for the creation of private variables within functions, enabling data encapsulation and information hiding. They also enable the implementation of callback functions and the concept of function currying. Additionally, closures contribute to the concept of lexical scope, where variables are resolved based on their position within the source code.

Overall, closures are a key aspect of JavaScript programming that provides a powerful mechanism for managing scope, accessing variables, and creating flexible and expressive functions.