From be50f1f076d2fc55898dd5ed82a863d549c433af Mon Sep 17 00:00:00 2001
From: Anthony GAEREMYNCK <1@anthony.sh>
Date: Fri, 31 Jul 2026 12:57:35 +0200
Subject: [PATCH] feat: add font MIME types and fix dfont/ico detection
 collision

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
---
 src/mime.js       | 12 ++++++++++++
 test/mime.test.js | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+)

diff --git a/src/mime.js b/src/mime.js
index 37f3578..ed99c7d 100644
--- a/src/mime.js
+++ b/src/mime.js
@@ -1,4 +1,6 @@
 import { fileTypeFromFile } from 'file-type';
+import fs from 'node:fs/promises';
+import { probeDfont } from './converters/dfont.js';
 
 const OUTPUT_MIME_TYPES = {
   jpg: 'image/jpeg',
@@ -17,6 +19,9 @@ const OUTPUT_MIME_TYPES = {
   md: 'text/markdown',
   csv: 'text/csv',
   xlsx: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
+  ttf: 'font/ttf',
+  otf: 'font/otf',
+  woff: 'font/woff',
 };
 
 export async function detectInputMime(filePath) {
@@ -46,6 +51,13 @@ function normalizeFormat(format) {
 }
 
 export async function resolveInputFormat(filePath, declaredFormat) {
+  if (declaredFormat === 'dfont') {
+    const buffer = await fs.readFile(filePath);
+    return probeDfont(buffer)
+      ? { mime: 'application/x-dfont', valid: true }
+      : { mime: null, valid: false };
+  }
+
   const detected = await detectInputMime(filePath);
 
   if (!detected) {
diff --git a/test/mime.test.js b/test/mime.test.js
index 1780bce..f46c121 100644
--- a/test/mime.test.js
+++ b/test/mime.test.js
@@ -104,3 +104,35 @@ describe('resolveInputFormat — heic/heif alias', () => {
     expect(result.valid).toBe(true);
   });
 });
+
+describe('outputMimeType — fonts', () => {
+  it('returns the correct MIME type for each font target format', () => {
+    expect(outputMimeType('ttf')).toBe('font/ttf');
+    expect(outputMimeType('otf')).toBe('font/otf');
+    expect(outputMimeType('woff')).toBe('font/woff');
+  });
+});
+
+describe('resolveInputFormat — dfont', () => {
+  it('confirms file-type alone misidentifies the dfont fixture as ico (documents the bug this fix works around)', async () => {
+    const fixturePath = path.join(import.meta.dirname, 'fixtures', 'sample.dfont');
+    const detected = await detectInputMime(fixturePath);
+    expect(detected.ext).toBe('ico');
+  });
+
+  it('accepts a real dfont file despite that misidentification', async () => {
+    const fixturePath = path.join(import.meta.dirname, 'fixtures', 'sample.dfont');
+    const result = await resolveInputFormat(fixturePath, 'dfont');
+    expect(result).toEqual({ mime: 'application/x-dfont', valid: true });
+  });
+
+  it('rejects content starting with the colliding magic bytes that is not a real dfont', async () => {
+    const fixturePath = path.join(import.meta.dirname, 'fixtures', 'sample-fake.dfont');
+    await fs.writeFile(fixturePath, Buffer.from([0x00, 0x00, 0x01, 0x00, 0x01, 0x00, 0x10, 0x10]));
+
+    const result = await resolveInputFormat(fixturePath, 'dfont');
+    expect(result).toEqual({ mime: null, valid: false });
+
+    await fs.unlink(fixturePath);
+  });
+});