A pure function is a concept borrowed from functional programming that is essential to understanding how to write predictable and maintainable code. In the context of ReactJS, as well as in general programming, a pure function has two main characteristics:
Deterministic Output: A pure function always returns the same result given the same input values. This means that the function's output is solely determined by its input parameters, without any reliance on external state, variables, or data that may change as the program executes[1][2][3][4][5][6][7][10][11][15].
No Side Effects: A pure function does not produce side effects, which means it does not alter any state outside of its scope. It does not modify any global variables, mutate its arguments, perform I/O operations, or interact with anything beyond its local environment[1][2][3][4][5][6][7][10][11][15].
The concept of pure functions is crucial in ReactJS because it leads to components that are predictable and easier to test. When a component's rendering is based on pure functions, it ensures that the same props will always produce the same output, which simplifies debugging and reasoning about the component's behavior[7][9][10].
In React, functional components can be considered pure if they adhere to these principles. However, it's important to note that while functional components should ideally be pure, they may not always be pure by default, especially if they utilize hooks to manage state or side effects[7][8][12]. To optimize functional components and treat them as pure, React provide...
