Here is a high-level roadmap for learning React.js:

Basic HTML, CSS, and JavaScript: Before diving into React, it's important to have a strong foundation in the basics of web development.

JavaScript concepts: Learn the core concepts of JavaScript such as arrays, objects, loops, functions, and more.

React Fundamentals: Start by learning the basics of React, including components, JSX, state, and props.

React Components: Learn about functional and class components, lifecycle methods, and how to manage state and props.

React Hooks: Learn about React Hooks and how to use them for state management and other tasks.

React Routing: Learn about React Router and how to add navigation to your React application.

React and API: Learn how to make API calls in React and how to handle API data.

React and Redux: Learn about the Redux library and how it can be used for state management in React applications.

React and Context API: Learn about the Context API and how it can be used for global state management.

React and Testing: Learn how to test React components and how to write unit tests for React applications.

Advanced React: Study advanced topics such as server-side rendering, performance optimization, and integrating with other libraries.

Note However, following this roadmap will give you a solid foundation in React and help you build production-ready applications.