Samuel Mehrbrodt
The browser-side build of Collabora Online had been quietly accumulating cruft: hand-maintained -webkit-, -moz-, -ms- and -o- vendor prefixes spread across many different CSS files, and no automated way to tell whether a given JavaScript API actually worked on the browsers our customers run. We had a vague sense of “modern enough”, but no rules.
One source of truth
We added an explicit browserslist to browser/package.json with absolute version floors:
“Chrome >= 120”, “Firefox >= 128”, “Safari >= 16.4”, “iOS >= 16.4”, “ChromeAndroid >= 120”, …
Floors are fixed for the lifetime of a yearly major release and bumped only at the next major. Bumping support is now a one-line diff, reviewed deliberately.
Two gates that enforce it
– autoprefixer (CSS) inserts vendor prefixes for exactly the targeted browsers at build time. Source CSS is now unprefixed.
– eslint-plugin-compat (JS) reads the same browserslist and errors when source uses runtime APIs not supported across the target set.
The size bonus
While we were in there, we replaced uglify-js with terser and bumped TypeScript’s target from ES5 to ES2022. The production bundle dropped from 4.50 MB to 3.34 MB, a 25.8% saving served on every (uncached) document open.
