# auto-boot

## Purpose

Pure side-effect entry imported by `suaveplan-font-compress.ts` for the
shebang-launch case. The only behaviour is: if the running file is the
`dist/bin/suaveplan-font-compress.js` binary (detected by the `argv[1]`
basename), dynamically import the bin entry and run `main(process.argv.slice(2))`,
then `process.exit` with the resulting code. The split exists so the
`process.exit` branch — which cannot be honestly exercised from in-process
without spawning a subprocess — can be excluded from coverage as a pure
boot stub while the surrounding `main()` (which does the actual work) is
fully covered by the in-process suites in this directory.

## Features

- Detects direct invocation via `process.argv[1]` rather than
  `fileURLToPath(import.meta.url)` so the check works regardless of the
  module's own location (auto-boot is a sibling of the entry, not the
  entry itself).
- Dynamic import of `./suaveplan-font-compress.js` so this module's static
  init does not depend on the bin entry's static init, avoiding any
  cyclic-import surprises with bundlers.
- Maps a successful `main()` resolve to `process.exit(code)`; maps a
  rejected promise to a stderr-printed message and `process.exit(1)`.

## Usage: Basic

The module has no exports — importing it as a side-effect is the entire
API:

```ts
// In suaveplan-font-compress.ts
import "./auto-boot.js";
```

## Usage: Advanced

```sh
# Direct shebang launch — boot runs through this module.
node dist/bin/suaveplan-font-compress.js ./fonts -o ./out

# In-process import — boot detects argv[1] does not end with the binary
# name and stays silent; tests can then call `main()` directly without
# accidentally launching a second instance.
import { main } from "@suaveplan/font-compress/bin/suaveplan-font-compress";
await main(["./fonts", "-o", "./out"]);
```

## API Reference

No public API. The module's side effect runs once at import time:

1. Check `process.argv[1]` for the binary basename suffix.
2. If matched, dynamically import the bin entry and call its `main`.
3. Map the resolved exit code to `process.exit(code)`; map a rejection
   to stderr write + `process.exit(1)`.

## Implementation Notes

`process.argv[1].endsWith("suaveplan-font-compress.js")` is intentionally
basename-based — the absolute path comparison used by single-file bin
patterns does not work here because auto-boot is a sibling, not the entry.
The `try/catch` around the check guards against environments where
`process` is undefined (some non-Node runtimes) and against any pathologic
`argv` shapes; both fall back to "not direct invocation" which is the safe
default for an import-only module. Coverage excludes this file because
every branch is either a `process.argv` predicate or a `process.exit`
side-effect — neither can be honestly faked from in-process.