() => Promise<void> | void
Called before a build begins, once per build. A watch rebuild is a build, so it fires again for each one.
(files: string[], durationMs: number) => Promise<void> | void
Called once a build has finished.
files is every file the build declares that is on disk, as absolute, platform-native paths, sorted. It is what the build declares rather than what it wrote this time, so a configuration the cache skipped contributes its files too, and a post-processing step sees the whole set on a rebuild that changed one file. A declared file Style Dictionary declined to write, such as one whose filter matched no tokens, is left out.(error: unknown) => Promise<void> | void
Called when a build fails, whatever
failOnError is set to, and before that option decides whether to rethrow. A failure inside Style Dictionary arrives wrapped in an Error whose message names the configuration it came from, with Style Dictionary’s own error as its cause. A failed rebuild also names the last file to change before it.What they cannot do
A hook is called and not awaited, so anasync hook runs beside the build rather than holding it up. A hook that throws is reported, and a promise that rejects is caught and reported rather than reaching the host as an unhandled rejection. Neither fails the build: deciding that is failOnError’s job.
The return type is Promise<void> | void so an async hook type-checks and passes type-aware lint rules such as no-misused-promises, not because its promise is waited on.