For junior or mid-level developers diving into the world of ReactJS, performance might not be the initial priority. However, it's essential to weave in efficiency from the get-go. Enter the concept of useCallback.
If you're scratching your head about what useCallback is, let's break it down. At its core, useCallback is a ReactJS Hook. For a deeper dive, follow the link provided (not included in this rendition).
The official explanation aptly encapsulates its essence, but let's make it even clearer:
Before we delve deeper, let's address the term memoized. Think of it as a technique to fast-track processes that are resource-intensive.
The given code illustrates the syntax: it's a function taking another function and an array of inputs (or dependencies).
What's the catch? The result is a memoized version of the initial function. Throughout the component's lifecycle, this cached reference remains consistent, unless the inputs (like a or b) change. So, if either input is altered, a new function version is generated. The magic lies in the optimization: instead of constantly allocating a new function (the anonymous function with the doSomething() call) with each component render, the component retains the memoized function.
In simpler terms, this hook ensures that the component starts with a unique function reference that remains constant during its lifecycle.
useCallback isn’t a cure-all solution. Not every function is a candidate for it. It’s paramount to recognize your function's inputs or dependencies. While useCallback can be a developer's boon, misuse might make it more of a burden.
Written by Julián Alzate