Terra Design System

Terra was Cerner’s open-source design system, the React component library under the Millennium platform. I was one of two UX designers on the project who could work directly in the React codebase alongside the engineers.

Healthcare UI components don’t get to be built wrong. A focus-trap bug in one alert propagates to every product that consumes it. A contrast failure shows up in an operating room. I made sure those things didn’t happen.

Most days I was in the monorepo reading pull requests, flagging where an engineer’s reasonable implementation had quietly diverged from the standard. I’d comment on the PR, cite the lines where the standard and the code came apart, and name what it required. Usually engineering made the change from there.

But I had commit access, and when I could see the fix I wrote it myself. I found a numeric input that, on mobile, accepted any string you typed in. That’s a data-integrity bug, not a cosmetic one, and it only showed up if you went looking on a phone. I reproduced the error and filed a bug with steps and a screenshot, handing engineering a working sandbox. They built from it.

The bigger thing I owned was the icon library. A visual designer drew the icons. I owned everything after that: the repository, the build, the versioning, the package the engineering team pulled straight into the component system (UX write-up). Every icon that shipped into a Cerner product came through that repository.

I came up on the web believing Jeffrey Zeldman’s line that real designers code, and it had been true everywhere I’d worked. Enterprise was where I learned it wasn’t always the default. Plenty of designers on my team didn’t write CSS, let alone read React. Being one of the two who could read the standard and the code both was the whole reason the role existed.