React as the docs says is a JavaScript library for building user interfaces.

• Declarative

  React makes it painless to create interactive UIs. Design simple views for each
  state in your application, and React will efficiently update and render just the
  right components when your data changes.
  

  Declarative views make your code more predictable and easier to debug.
  In addition, React declarative nature make it very easy, in sense that, you just tell
  it what you want and React will effectively do the hard work for you.
  

• Component-Based

  Build encapsulated components that manage their own state, then compose them to make complex UIs.
  Since component logic is written in JavaScript instead of templates, you can easily pass rich data
  through your app and keep state out of the DOM.

• Good Knowledge about HTML and CSS.
• Good understanding of JavaScript basic more importantly ES6 or ECAMScript 6 or ES2016
  stuff like let, const, arrow function, classes, array methods like map, filter etc.
• Basic knowledge of Node and npm (commands)

1. Introduction to React
2. Introduction to JSX
3. Introduction to React Elements
4. Components
   1. Stateless Components
   2. Stateful Components
5. Props and State
6. Virtual DOM
7. Conditional Rendering
8. Handling Events
9. Handling Forms
10. Lifting State Up
11. lifeCycle Methods
    1. componentDidMount
    2. componentWillUnmount
12. Hooks
13. Routing
14. Fetch