Function Expression
A function expression is a JavaScript construct that defines a function as part of a larger expression, typically by assigning it to a variable. Unlike function declarations, function expressions are not hoisted and can be anonymous or named, allowing for flexible usage in various programming contexts. They are fundamental to JavaScript's functional programming capabilities and are widely used for callbacks, closures, and module patterns.
Developers should learn function expressions for creating reusable, scoped functions that can be passed as arguments, returned from other functions, or used in event handlers and asynchronous operations. They are essential for implementing higher-order functions, managing private variables with closures, and writing clean, modular code in modern JavaScript frameworks and libraries.