Filter Function
A filter function is a higher-order function in programming that processes a collection (like an array or list) by applying a predicate (a function returning a boolean) to each element, returning a new collection containing only the elements for which the predicate returns true. It is a fundamental concept in functional programming and is widely implemented in many programming languages and libraries to enable declarative data manipulation. This function promotes immutability by not modifying the original collection, making code more predictable and easier to reason about.
Developers should learn and use filter functions when they need to selectively extract elements from a collection based on specific conditions, such as filtering out invalid data, selecting items that meet certain criteria, or preprocessing data for further operations. It is particularly useful in data processing pipelines, UI rendering (e.g., filtering lists in web applications), and functional programming patterns, as it enhances code readability, reduces boilerplate, and aligns with principles like pure functions and immutability.