__DEV__ Gating

Three layers of stripping:

1. Runtime — is_dev() reads globalThis.__DEV__ if set, else falls back to process.env.NODE_ENV !== "production". Set globalThis.__DEV__ = false early in your bootstrap to globally disable debug output.
2. debug({ dev: false }) — short-circuit individual debug instances.
3. debug_noop() — a zero-overhead stub. Pass into the harness/boot when you want compile-time tree-shaking of debug calls (production builds).

Bundler-define pattern (rolldown/rolldown-vite):

rolldown.config.ts

export default {
  // ...
  define: {
    __DEV__: process.env.NODE_ENV === "production" ? "false" : "true",
  },
};

When __DEV__ resolves to a literal false, dead-branch elimination drops the debug emit calls entirely.