Expose detectMimeType (#41)

Author: educastellano

README.md

@@ -267,6 +267,16 @@ Helpers to check supported media types are exposed in `bare-media/types`:
 - `isMediaSupported(mimetype)`: returns `true` if the mimetype is either a supported image or video format.
 - `isStripMetadataSupported(mimetype)`: returns `true` if `metadata.strip()` supports the mimetype.
 
+Detect the MIME type of a buffer:
+
+```js
+import { detectMimeType } from 'bare-media'
+
+const mimetype = detectMimeType(buffer)
+```
+
+> This may return non-media MIME types, use `isMediaSupported()` to validate support.
+
 ## License
 
 Apache-2.0

src/codecs.js

@@ -1,3 +1,6 @@
+import getMimeType from 'get-mime-type'
+import getFileFormat from 'get-file-format'
+
 import { IMAGE } from '../types'
 
 export const codecs = {
@@ -41,3 +44,7 @@ export async function importFFmpeg() {
 export function supportsQuality(mimetype) {
   return { 'image/webp': true, 'image/jpeg': true }[mimetype] || false
 }
+
+export function detectMimeType(buffer) {
+  return getMimeType(getFileFormat(buffer))
+}

src/image.js

@@ -1,10 +1,10 @@
 import fs from 'bare-fs'
 import fetch from 'bare-fetch'
 
-import { EXIF } from '../types'
-import { importCodec, supportsQuality } from './codecs'
+import { EXIF } from '../types.js'
+import { importCodec, supportsQuality, detectMimeType } from './codecs.js'
 import { metadata, ImageMetadataPipeline } from './image/metadata'
-import { isHttpUrl, detectMimeType, calculateFitDimensions } from './util'
+import { isHttpUrl, calculateFitDimensions } from './util'
 
 const animatableMimetypes = ['image/gif', 'image/webp']
 

src/image/metadata.js

@@ -1,5 +1,6 @@
 import { IMAGE } from '../../types.js'
-import { detectMimeType, isHttpUrl } from '../util.js'
+import { detectMimeType } from '../codecs.js'
+import { isHttpUrl } from '../util.js'
 
 const supportedExifMimetypes = new Set([IMAGE.JPEG, IMAGE.JPG, IMAGE.TIFF, IMAGE.TIF])
 

src/util.js

@@ -1,10 +1,3 @@
-import getMimeType from 'get-mime-type'
-import getFileFormat from 'get-file-format'
-
-export function detectMimeType(buffer) {
-  return getMimeType(getFileFormat(buffer))
-}
-
 export function calculateFitDimensions(width, height, maxWidth = Infinity, maxHeight = Infinity) {
   if (width <= maxWidth && height <= maxHeight) {
     return { width, height }

test/common.js

@@ -1,6 +1,7 @@
 import { test } from 'brittle'
 
-import { calculateFitDimensions, detectMimeType } from '../src/util'
+import { detectMimeType } from '../index'
+import { calculateFitDimensions } from '../src/util'
 
 // util
 
@@ -50,7 +51,7 @@ test('util calculateFitDimensions()', async (t) => {
   }
 })
 
-test('util detectMimeType()', async (t) => {
+test('detectMimeType()', async (t) => {
   t.is(detectMimeType(Buffer.from([0xff, 0xd8, 0xff])), 'image/jpeg')
   t.is(detectMimeType(Buffer.from([0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a])), 'image/png')
   t.is(detectMimeType(Buffer.from([0x47, 0x49, 0x46, 0x38])), 'image/gif')