If you spend a lot of time doing front-end development, you know how big the the world of HTML, CSS and JavaScript are. I came up with this list of topics after chatting with several different front-end developers over the past nine months. Some of the topics also came from my own experiences working as a full-time front-end engineer for the past three years.

The list (written in no particular order) may feel a bit intimidating now, but I am remaining optimistic about being able to continually grow my knowledge about each of these topics and hopefully commit them to memory as I use them in the wild. I actually decided to create this list after feeling a bout of imposter syndrome today at work. Now, I'm feeling excited to continue digging into each topic further!

1. The Document Object Model (DOM) and CSS Object Model (CSSOM)
2. The JavaScript Event Loop, Promises, Asyc/Await
3. CSS position Property
4. CSS Flexbox Layout
5. HTML Roles
6. Common Accessibility Issues to Always Check For
7. Unit & Integration Testing (Jest, Mocha, Chai, Cypress, Axe-Core)
8. Form action and target Attributes
9. JavaScript Design Patterns
10. Closures and Thunks
11. CSS Variables and Preprocessors
12. JavaScript as a Statically Typed Language (TypeScript)
13. Mutable and Immutable Types in JavaScript
14. JavaScript Passed by Reference / Passed by Value
15. JSON Data, JSON-LD, JSON Schemas & UI Schemas
16. HTML Meta Tags (Especially Viewport)
17. Different Ways Pages Zoom and How To Optimize For That
18. Front-End Frameworks (React, Vue, Angular)
19. HTML Templating (Handlebars, EJS)
20. Webpack / Babel
21. Git, Version Control and Rebasing
22. Jenkins, Docker, Continuous Integration
23. Caching
24. CSS Methodologies (i.e. BEM)
25. JavaScript Array Methods: .sort(), .filter(), .map(), .reduce()
26. JavaScript Object Methods: .keys(), .entries(), .values()
27. Front-End Performance Optimization & Speed
28. CSS Specificity and Inheritance
29. State Management (i.e. Redux)
30. Semantic HTML
31. Communicating with RESTful APIs

Feel free to leave a comment below if you have any suggestions for more topics to add to the list. Also, feel free to hit me up on Twitter @Contimporary to follow my journey to become a senior developer!