# db/builtin-db

## Purpose

The built-in MIME type database for `@suaveplan/mime`. Contains over 150 `MimeEntry` records covering the most common web, media, document, archive, font, and application MIME types. This is a static data file — it contains no runtime logic, only the `BUILTIN_DB` constant array consumed by the registry.

## Features

- 150+ MIME type entries across all major categories
- Each entry includes: `mime` (canonical type string), `extensions` (array of associated file extensions), and `encoding` (`"binary"`, `"text"`, or `"base64"`)
- Comprehensive coverage: images, audio, video, documents, archives, fonts, executables, data formats
- Extensions are lowercase and without leading dots
- Canonical extension (for `Content-Disposition` filename guessing) is always the first element

## Usage: Basic Example

```typescript
import { BUILTIN_DB } from "@suaveplan/mime/db/builtin-db";

// Inspect all text-type entries
const textTypes = BUILTIN_DB.filter(e => e.mime.startsWith("text/"));
console.log(textTypes.map(e => e.mime));
// ["text/plain", "text/html", "text/css", ...]
```

## Usage: Advanced Example

```typescript
import { BUILTIN_DB } from "@suaveplan/mime/db/builtin-db";
import { getEntryByMime } from "@suaveplan/mime/db/registry";

// Combine built-in with runtime lookup
const entry = getEntryByMime("application/pdf");
console.log(entry?.extensions); // ["pdf"]
console.log(entry?.encoding);   // "binary"

// Find all binary MIME types
const binaryTypes = BUILTIN_DB.filter(e => e.encoding === "binary");
console.log(binaryTypes.length); // 100+
```

## API Reference

### `BUILTIN_DB: readonly MimeEntry[]`

A frozen array of `MimeEntry` objects. Each entry has:

| Field | Type | Description |
|-------|------|-------------|
| `mime` | `string` | Canonical MIME type string (e.g., `"image/png"`) |
| `extensions` | `string[]` | Associated file extensions without dots (e.g., `["png"]`) |
| `encoding` | `"binary" \| "text" \| "base64"` | Transfer encoding hint |

## Implementation Notes

The database is intentionally a plain array rather than a pre-built map so that the registry can apply its first-write-wins semantics during initialization. Keeping data and behavior separate also makes it straightforward to swap the database at build time (e.g., for a minimal embedded build that includes only a subset of MIME types). The entries are ordered roughly by frequency of use, which has no algorithmic impact but improves grep readability.