Variable parameter lists
Reflect and Proxy are built-in objects that allow for modification of a program at runtime. These objects include a global Reflect object, and static methods for introspection. They are useful for discovering low-level information about the code. Moreover, the Reflect API allows for automated testing frameworks that use a ‘Reflection’ object. Object introspection is possible through both Reflect and Proxy.
React JS monitors the state of components with Virtual DOM. Then, it uses this information to update the DOM in the least expensive way. This way, the developer can avoid trashing the layout. This is important because most applications are viewed on mobile devices. With React JS, you’ll avoid this problem because it uses a component-based approach that’s easy to understand. The React JS library is available on npm.