React

React is a framework that works with Javascript to render dynamic page content. It maintains a state variable for each dynamic element that is controlled using components made using classes or functions and hooks.

This competency area includes managing controlled components, routing with Params, fetching, and processing data using web requests, among others. 

Key Competencies:

1. Components and Props (Controlled Components, Multiple, Component Lifecycle) - Manage controlled components through hooks or using setState(), familiarity with passing properties from one component to another, familiarity with the component lifecycle, e.g. (un)mounting, updating, error handling
2. Routing with Params - Rendering views based on parameters in the URL and creating navigation bars.
3. Use APIs - Fetching data using web requests, process and display data retrieved
4. Basic Hooks (useState, useEffect) - Familiarity with the two most commonly used hooks: useState and useEffect.
5. Controlled and Uncontrolled Components