- The react docs say that contact with vital way to pass data through the component tree without having to pass prompts down manually at every level. So why do we need context, if we can pass props down? Well, it solves a problem in complex component hierarchies and it cleans up component code. We've got a simple component tree here that only has two branches and three levels where propX is used in two components on the bottom level. Imagine that we have 10 branches with 30 levels and various components at different levels in the tree each use propX. That's a lot of extra code because each parent, grandparent, great-grandparent and so on in the tree must pass propX down. Even if it doesn't use the value itself, if one of its children do. Context allows a component high in the tree to provide props to components lower in the tree without the need to pass props through every component. The provider is needed at the prop source and a consumer at the component that uses it. So what are the use cases for context? Realistically, there's only one real reason to use context, and that's why multiple components across multiple trees need to access the same value. So for example, a set of color styles needed in components across an application would be a perfect use case for context. Note, that if you work in a single tree, context shouldn't really be used to simply bypass components passing props down through them.

Lectures

Introduction to State Management - How to Create and Provide Context - Consume Context - Reducers - Actions in Reducers - The useReducer Hook - Providing Dispatch