What’s new with React? New lifecycle methods, context API, hooks, and lots more. While the fundamental principles of React have stayed the same, the way we write React apps has changed with each new release.  

If you learned React a while back, it’s possible that you haven’t been up to date with every new feature/release. It’s also possible to get lost in all the new features. Where exactly do you start? How important are they for your day to day use?

This course is your one-stop reference to most important React updates since V16 was released. We’ll walk through all the major features of modern React so you can stay in sync with the most recent changes while learning to write better software.

Reintroducing React: V16 and Beyond

### Components Rendered Needlessly

First, let’s consider what’s likely to be the root of the problem here. By default, whenever a `Provider` has its `value` changed, every child component is forced to re-render. That’s how the `Consumer` gets the latest values from the `context` object and stays in sync. 

The problem here is that every component apart from `Root` is a child of `Provider` and they all get re-rendered needlessly! 



# Components Rendered Needlessly

First, let’s consider what’s likely to be the root of the problem here. By default, whenever a `Provider` has its `value` changed, every child component is forced to re-render. That’s how the `Consumer` gets the latest values from the `context` object and stays in sync. 

The problem here is that every component apart from `Root` is a child of `Provider` and they all get re-rendered needlessly! 



Let's take a look at the flow of the Flamegraph for our bank app.

Introduction

Lifecycle

Context API

ContextType

React.memo

The Profiler

Lazy Loading

Hooks

Conclusion

Interpreting the Flamegraph

Components Rendered Needlessly