Reactivity is the mechanism that allows the framework to detect when data used on the page is changed (mutated), and to update the page optimally to reflect these changes.
Templating refers to the way a framework allows developers to structure and render the UI. It includes how HTML-like structures are created, how dynamic content is inserted, and how the UI reacts to data changes.
Lifecycle hooks are methods that allow developers to run code at specific points in a component's life, such as when it's created, updated, or destroyed. Understanding these hooks is crucial for managing side effects and optimizing performance.
Component composition is a fundamental concept in modern frontend frameworks. It involves breaking down the UI into reusable pieces, and understanding how these pieces can communicate and work together to build complex applications.