# errors/mime-error

## Purpose

The base error class for all `@suaveplan/mime` errors. Extends `SuaveplanError` from `@suaveplan/error` with the `MIME_ERROR_CODES` namespace and provides a common ancestor for `instanceof` checks across all MIME-specific error types.

## Features

- Extends `SuaveplanError` for consistent error serialization and OTel integration
- `code` field set to `MIME_ERROR_CODES.INVALID_CONTENT_TYPE` by default (overridden by subclasses)
- `name` property set to `"MimeError"` for easy identification in logs
- Compatible with `SuaveplanError`'s cause-chain traversal and redaction APIs
- Used as the base for `instanceof MimeError` checks when callers don't need the specific subtype

## Usage: Basic Example

```typescript
import { MimeError } from "@suaveplan/mime/errors";

try {
    // Any MIME operation
} catch (err) {
    if (err instanceof MimeError) {
        console.error("MIME error:", err.message, "code:", err.code);
    }
}
```

## Usage: Advanced Example

```typescript
import { MimeError } from "@suaveplan/mime/errors";
import { InvalidContentTypeError, UnknownMimeTypeError } from "@suaveplan/mime/errors";

// Route by specific subtype
function handleMimeError(err: MimeError) {
    if (err instanceof InvalidContentTypeError) {
        return Response.json({ error: "bad_content_type" }, { status: 400 });
    }
    if (err instanceof UnknownMimeTypeError) {
        return Response.json({ error: "unsupported_type" }, { status: 415 });
    }
    throw err; // Unexpected subtype — re-throw
}
```

## API Reference

### `class MimeError extends SuaveplanError`

The base class. All `@suaveplan/mime` error classes extend this.

## Implementation Notes

`MimeError` exists primarily to provide a stable `instanceof` target for callers who want to catch any MIME-related error without caring about the specific subtype. All subclasses set their own `code` from `MIME_ERROR_CODES` and override `name` with their class name. The inheritance chain is: `SuaveplanError → MimeError → {subtype}`.

### Subclass Index

Direct subclasses are `InvalidContentTypeError`, `UnknownMimeTypeError`, `UnknownSignatureError`, `InsufficientBytesError`, and `ParseError`. Every subclass sets its own `code` from the stable `MIME_ERROR_CODES` registry, overrides `name`, and inherits the wire-serialisation, OTel span-event adapter, and i18n resolver behaviour from `SuaveplanError`. Tests typically assert `err instanceof MimeError` first for broad catches, then narrow with `instanceof` on the specific subclass.