zopu-code/repos/effect/.changeset/clean-needles-shake.md

effect

effect
patch

Fix module-level side effects that defeated bundler tree-shaking.

Bare top-level statements cannot be #__PURE__-annotated by the build, so bundlers must retain them and everything they reference, even in bundles that never use the code:

• Option: the standalone Object.defineProperty(SomeProto, "valueOrUndefined", ...) statement anchored the whole Option proto chain into every bundle. It is now folded into the SomeProto initializer.
• Headers: same pattern with Object.defineProperties(Proto, ...), folded into the initializer.
• Logger: module-level process.stdout.isTTY property reads (potential getters, never droppable) moved inside consolePretty.
• Utils: when internalCall was unused, its dropped binding left behind a retained initializer tail (standard/forced probe with computed property reads). The selection is now wrapped in a single pure-annotated call.

A minimal Effect.succeed(123).pipe(Effect.runFork) bundle shrinks by ~1.3% gzipped; bundles that don't use Option or Headers no longer pay for them.