ReactJS React Basics Syllabus

React Basics syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for React Basics in ReactJS, not a summary of it.

1. 1

   Introduction to React

   3 topics

   • What is React?
   • History of React
   • Why use React?
2. 2

   Setting Up the Environment

   3 topics

   • Node.js and npm
   • Create React App
   • Folder Structure
3. 3

   JSX

   3 topics

   • What is JSX?
   • JSX Syntax
   • Embedding Expressions in JSX

React Basics flashcards for ReactJS

18 of 51 cards from the React Basics deck — real questions with worked answers.

1. What is React?

   React is an open-source JavaScript library for building user interfaces, especially single-page applications, using reusable, component-based UI pieces.

2. Is React a library or a full framework?

   React is a library (focused on the view/UI layer), not a full framework; it relies on additional libraries for routing, state management, etc.

3. Which company created and maintains React?

   Meta (Facebook), along with a large open-source community of individual developers.

4. In which year was React first released publicly?

   React was first released publicly in 2013 (open-sourced in May 2013).

5. Who is credited as the creator of React?

   Jordan Walke, a software engineer at Facebook, created React.

6. What early Facebook prototype did React evolve from?

   It evolved from 'FaxJS', and was influenced by Facebook's earlier XHP (an HTML component library for PHP).

7. On which Facebook product was React first deployed before open-sourcing?

   React was first used in Facebook's News Feed (2011) and later on Instagram (2012).

8. What is the Virtual DOM in React?

   The Virtual DOM is a lightweight in-memory JavaScript representation of the real DOM that React uses to compute minimal, efficient updates.

9. What process does React use to update the real DOM efficiently?

   Reconciliation (diffing): React compares the new Virtual DOM with the previous one and applies only the minimal set of changes to the real DOM.

10. Name three key reasons developers choose to use React.

    Reusable component-based architecture, efficient updates via the Virtual DOM, and a large ecosystem/community with strong tooling and reusability.

11. What programming paradigm does React follow for describing UI?

    A declarative paradigm: you describe what the UI should look like for a given state, and React handles updating the DOM.

12. What is the difference between declarative and imperative UI in the context of React?

    Declarative (React): you state the desired end result and React figures out the DOM changes. Imperative (e.g., vanilla JS): you manually write step-by-step DOM manipulation instructions.

13. What direction does data flow in React by default?

    One-way (unidirectional) data flow: data passes from parent to child components via props.

14. What is a React component?

    A component is an independent, reusable piece of UI, typically a JavaScript function (or class) that returns markup describing what should appear on screen.

15. What are 'props' in React?

    Props (properties) are read-only inputs passed from a parent component to a child component to configure or customize it.

16. What is Node.js?

    Node.js is a JavaScript runtime built on Chrome's V8 engine that lets you run JavaScript outside the browser, e.g., on a server or for build tooling.

17. Why is Node.js needed for React development?

    React tooling (bundlers, dev servers, package management) runs on Node.js, and npm ships with Node to install and manage project dependencies.

18. What does npm stand for?

    npm stands for Node Package Manager.

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