Reusing components is the major advantage of React JS. Even Facebook has implemented React as it facilitates the reuse of system components. A developer can start with usual components like checkbox, button, etc. Once this is done you can move to wrapper components comprised of internal logic which makes it easier to manipulate and define objects used. This ensures consistency of application and facilitates code maintenance. Many companies like Walmart tend to use ReactJS. As all companies have common components like payment form elements, image carousel, bread crumbs, for example. Here comes into picture the reuse of components. Also to enable version management and further install components there are coding standards defined to maintain uniformity. This also enhances the speed of the application, which enjoys more customer retention.
The performance of any application depends upon the structure on which it is built. For building a high load application this is one of the major factors which is to be considered. But engines that are used these days cannot ensure bottlenecks because DOM (document object model) is tree-structured and even small layers can make drastic changes. To resolve this Virtual DOM was introduced. ReactJS can be used for heavy loaded and dynamic solutions. It is a virtual representation on the document object model and checks if all changes are applied to the virtual DOM. The real DOM tree is later updated and it also ensures that minimum time is consumed for this purpose. Using this method guarantees better user experience and performance.
ReactJS uses downward data flow. This is because it ensures that smallest of changes that happen in child structure do not affect the parents. When an object is changed by a developer it needs to be made sure that only the particular objects are updated and that just its state is modified. The data is bound together with the object and this structure sees to it that code stability and application performance is maintained.
Flux architecture was developed by Facebook for its various web applications. It is similar to React components by its unidirectional flow. This architecture has action creators that help in creating action from method parameters. It also maintains a library for these methods. All these actions are kept together by a central dispatcher to update stores. All views are updated as per the stores. There is also Redux which is an improved version of flux architecture. It has a single store which is not present in flux. Redux also enables a feature where middleware can be defined to intercept dispatched actions.
Another important uses of React JS is a user-friendly development platform. The two major tools provided are React to Developer Tools and Redux Developer Tools. Both these tools can be installed as Chrome extensions. React developer tool is used for inspecting react components that lie in a hierarchy and are used for introspecting current properties and states. It also helps to view component hierarchies, discover child and parent components as well. When using Redux you can observe various dispatched actions, current store states and check changes on stores. The different dispatch actions or modify stores with different changes can also be reflected and viewed instantly. A user can also record and go back to any previous states of the application for debugging purposes.
React is used worldwide due to its easy nature. Once you learn it you have scope in all major companies. Companies like Airbnb, Tesla, etc. use React Native for their applications. You can get a great career once you learn ReactJS.