No, you do not need to have prior knowledge of React.js to work with React Native. Although React Native is based on React.js, they are separate frameworks designed for different purposes. React.js is a JavaScript library primarily used for creating web applications, whereas React Native is specifically for building mobile applications.
That being said, having a fundamental understanding of JavaScript is crucial for working with React Native. Since React Native utilizes JavaScript, being familiar with the language basics is necessary to write code and comprehend React Native concepts.
While React Native shares some similarities with React.js, such as the component-based architecture and JSX syntax, they also have significant differences. React Native uses components that are specifically designed for mobile app development and provides access to native mobile features.
If your primary focus is on mobile app development, it is recommended to learn React Native directly. React Native has its own set of concepts and APIs that are essential for building efficient and performant mobile applications. However, if you already have experience with React.js, you might find it easier to grasp React Native concepts and get started quickly.