@dotworkout/codec

Decodes and encodes the Apple .workout binary format. No validation, no unit conversion, no opinions — bytes in, message out, and back again byte for byte.

import { decode, encode, findUnknownFields } from "@dotworkout/codec";

const workout = decode(bytes);
workout.customWorkout?.displayName;

encode(workout); // byte-identical to the input if you changed nothing

decode() branches on which container the file uses — field 10 (SingleGoalWorkout) or field 11 (CustomWorkout) — and throws on anything else rather than guessing.

findUnknownFields() walks the whole message tree and reports fields the schema does not model. Round-tripping a file byte-identically does not prove the schema is complete; protobuf keeps unrecognised fields and writes them back out. This is how you check.

To build and validate workouts rather than just read them, use @dotworkout/domain.

Format notes, provenance and open questions: github.com/javierferrersb/dotworkout

Credits

The protobuf schema started from changeforan/DotnetWorkoutKit (MIT). Ten missing fields and enum values were added; see spec/FORMAT.md §8 in the repo. No code was taken.

Not affiliated with Apple.

Licence

MIT. See LICENSE.