TypeScript

Types that pay for themselves

TypeScript is JavaScript with a type system on top: the code you write compiles down to plain JavaScript, but before that the compiler checks that every function receives what it expects and returns what it promises. In practice, that turns a whole category of error, the classic undefined in production, into a warning in your editor minutes after the code is written, not weeks later.

We use TypeScript by default on medium and large projects, on the front end with Vue and on the back end with Node. The criterion is honest: for a small script or a throwaway prototype, typing can be unnecessary ceremony, and plain JavaScript does the job. But when code will be maintained for years and touched by more than one person, types become documentation that does not go stale and a safety net for refactoring without fear.

For the people paying for the project, the effect shows up in maintenance. A typed codebase takes large changes with more confidence: the compiler points to every affected spot before anything ships. It also shortens onboarding for new developers, because the editor's autocomplete shows what each part of the system expects, without relying on separate documentation or on the memory of whoever wrote it.

• Node APIs with typed contracts
• Large Vue front ends
• Shared libraries and SDKs across projects
• Integrations with runtime data validation
• Types shared between front and back