Section 5 · Writing Real Programs
Where to Go Next
9 min3 min read
Lesson at a glance
Review what you can now build with JavaScript, pick a sensible next step among TypeScript, a framework, testing and accessibility, and plan practice that keeps your skills growing.
No video here — just the real thing: a written lesson, runnable examples, a quiz and practice.
Think back to the first lesson, when console.log(450 + 1200) was a complete program. Since then you have built Pocket: an app that validates input, keeps its data in a single state object, renders a filtered list with totals, handles clicks through one delegated listener, saves to storage, and is organised into modules with clear jobs. You also know why each piece works, from what = really does to the order in which the event loop runs callbacks.
That foundation does not expire. Frameworks come and go; variables, functions, arrays, objects, the DOM, events and promises are what all of them are made of.
Keep building
The single most effective next step is to build things nobody has told you how to build. Some ideas, roughly in order of difficulty:
- Extend Pocket: add a date to each expense and a “this month” view; set a budget per category and warn when it is close; let users edit an expense; export the data as a CSV file.
- A habit tracker: tick off habits each day and show streaks. It uses dates, storage and rendering, and nothing more.
- A quiz app that loads questions from a JSON file with
fetchand keeps a score. - Rebuild a small site you use: a to-do list, a unit converter, a pomodoro timer.
Expect to get stuck. Getting stuck, looking things up on MDN, and debugging your way out is the actual skill, and it only grows by doing it.
Where to go from here
Each of these builds directly on what you now know, and each solves a problem you have already felt:
- TypeScript adds types to JavaScript, so a string arriving where Pocket expects a number of cents becomes an error in your editor instead of a bug in production. When you are comfortable, Advanced TypeScript Patterns goes much further.
- A UI framework such as React takes the “state, update, render” pattern from the last lesson and makes it scale to large apps. React Fundamentals assumes exactly the JavaScript you just learned.
- Testing: your pure functions in
expenses.jsare perfect for automated tests that prove they work and keep working. Testing JavaScript Apps starts there. - Accessibility: you have used labels,
aria-invalidand real buttons; Web Accessibility in Practice makes it a habit for every interface you build. - Git: start saving your projects with Git & GitHub now, so you have a history of your progress and a portfolio to show.
Habits worth keeping
Keep MDN open while you code; it is the reference professional developers use daily. Read every error message to the end before searching for it. When something behaves strangely, check real values with a log or a breakpoint before changing code. And write small functions with clear names: future you is the person most likely to read your code.
Key takeaways
- You can now write programs that model data, make decisions, transform lists, update a page, handle input, save data and talk to servers.
- The fastest way to grow from here is building your own small projects, end to end, more than reading about new tools.
- TypeScript, a framework such as React, testing and accessibility all build directly on what this course taught, and each solves a problem you will now recognise.
- MDN is the reference to keep open; read error messages fully and debug with evidence before searching for answers.