TypeScript for JavaScript Developers
Like Duolingo, but for TypeScript for JavaScript Developers. Tomo turns the whole topic into a game you play five minutes a day, until it actually sticks.
For the part of you with thirty open tabs that never became anything.
Free forever · No credit card · iPhone & Android
Key ideas in TypeScript for JavaScript Developers
- TypeScript performs static analysis while you write code
- TypeScript looks at the initial value to assign a type automatically
- Errors are caught in the editor before the code is ever executed
- Manual type labels are optional when the intent is clear from the code
- Type inference automatically determines types from assigned values
- Red squiggles appear instantly when code violates a type contract
- TypeScript identifies errors during development rather than at runtime
- The editor compares your usage against the defined shape of the data
- Hovering over a variable shows its type definition
- The red squiggle identifies specific data mismatches
- Hovering reveals the expected structure of variables
- The 'any' type tells TypeScript to stop checking for errors on that variable
- Using 'any' bypasses the protection that prevents app crashes
- The 'any' type disables TypeScript's safety checks
- TypeScript uses interfaces to validate that an object contains all required properties
- The compiler will flag a missing property as an error before the code runs
You've tried the other tabs
Thirty open tabs. Four facts you actually kept.
You watched. You nodded. By Sunday it was gone.
One answer, then back to scrolling.
Eight weeks. You meant to finish. You didn't.
Tomo gives TypeScript for JavaScript Developers the Duolingo treatment: levels, streaks, and quick quizzes that test what you just learned. That game loop is what the tabs above never had, so it's the one you actually finish.
Here's what playing it feels like
A real question from this course. Take your best guess.
If you write 'let score = 100', how does TypeScript know that 'score' should be a number?
Get it right to open this lesson and 10 more in the app.
Where TypeScript for JavaScript Developers takes you
Upgrade your JavaScript workflow by catching bugs before they happen. Learn to use TypeScript as a powerful safety net that makes your code easier to write and harder to break.
- 1
The Safety Upgrade
- Catching Bugs Before They Run
- Defining Your Data's Shape
- 2
Working with the Real World
- Bulletproofing Your Functions
- Integrating with Existing Projects
2 sections · 4 units · 11 levels. Built to play, not to enroll.
You pick the voice
TypeScript for JavaScript Developers is taught in the The Bestie style: your friend who just gets it. Want a different feel? In the app you can spin up the same topic in any of Tomo's teaching styles. Same facts, totally different vibe.
More Technology on Tomo
Thinking Like a Security Manager
Learn to view the digital world through the lens of the CISSP. You'll move beyond technical fixes to understand the high-level strategies that keep global organizations safe.
Thinking Like a Programmer
Learn to speak the language of logic. This course transforms the way you solve problems by teaching you how to give precise, powerful instructions to a computer.
Instagram Growth for Photographers
Move beyond basic posting and learn how to turn your photography portfolio into a high-engagement community by avoiding common growth traps and mastering the modern algorithm.
The Solo Developer's System Design
Master the architectural patterns and deployment strategies needed to build, ship, and maintain professional-grade web applications without a team.
Business Automation with n8n
Move beyond simple triggers to build complex, AI-powered business systems. Learn to orchestrate data, integrate LLMs like Claude, and solve real-world consulting challenges with node-based logic.
Ham Radio: Your First License
Get ready to pass your Technician Class exam and join the global community of amateur radio operators. Learn how to talk across town or into space using the right frequencies and rules.
Start TypeScript for JavaScript Developers today.
Download Tomo, search TypeScript for JavaScript Developers, and play your first lesson in under a minute.