How do I write pure functions in JavaScript?

How do I write pure functions in JavaScript?

Pure functions are functions that always return the same output for the same input and do not cause any side effects. To write a pure function, ensure it doesn't modify any external state or rely on mutable data.

Can you give me an example of a pure function?

Sure! Here's a simple example:

function add(a, b) {
    return a + b;
}

This function always returns the same result for the same inputs and doesn't modify any external variables.

What are the benefits of using pure functions?

Pure functions are easier to test, debug, and reason about. They also enable better optimization by the JavaScript engine and make your code more predictable.

Are there any common mistakes to avoid when writing pure functions?

Yes, common mistakes include modifying external variables, using random values, or relying on global state. Always keep your functions self-contained.