FileType (identify MIME-type)
ts
function FileType(filename: string): string;Identifies the MIME type of a file by reading up to the first 261 bytes of its contents. This process is fast and memory-efficient, even for large files, because it does not require reading the entire file.
| Parameter | Type | Requirement | Explanation |
|---|---|---|---|
filename | string | required | Fully qualified path to an existing file |
| Return value | Explanation |
|---|---|
| string | The MIME type of the file, if identified; otherwise, an empty string |
The following are some of the file types that this function can identify:
| Category | Typical extension(s) | Returned MIME-Type |
|---|---|---|
| Image | jpg, jpeg | image/jpeg |
| Image | png | image/png |
| Image | gif | image/gif |
| Image | webp | image/webp |
| Image | cr2 | image/x-canon-cr2 |
| Image | tif, tiff | image/tiff |
| Image | bmp, bmp2 | image/bmp |
| Image | heif | image/heif |
| Image | jxr | image/vnd.ms-photo |
| Image | psd | image/vnd.adobe.photoshop |
| Image | ico | image/x-icon |
| Image | dwg | image/vnd.dwg |
| Video | mp4 | video/mp4 |
| Video | m4v | video/x-m4v |
| Video | mkv | video/x-matroska |
| Video | webm | video/webm |
| Video | mov, qt | video/quicktime |
| Video | avi | video/x-msvideo |
| Video | wmv | video/x-ms-wmv |
| Video | mpg | video/mpeg |
| Video | flv | video/x-flv |
| Video | 3gp | video/3gpp |
| Audio | mid | audio/midi |
| Audio | mp3 | audio/mpeg |
| Audio | m4a | audio/m4a |
| Audio | ogg | audio/ogg |
| Audio | flac | audio/x-flac |
| Audio | wav | audio/x-wav |
| Audio | amr | audio/amr |
| Audio | aac | audio/aac |
| Archive | epub | application/epub+zip |
| Archive | zip | application/zip |
| Archive | tar | application/x-tar |
| Archive | rar | application/x-rar-compressed |
| Archive | gz | application/gzip |
| Archive | bz2 | application/x-bzip2 |
| Archive | 7z | application/x-7z-compressed |
| Archive | xz | application/x-xz |
| Archive | application/pdf | |
| Archive | exe | application/x-msdownload |
| Archive | swf | application/x-shockwave-flash |
| Archive | rtf | application/rtf |
| Archive | iso | application/x-iso9660-image |
| Archive | eot | application/octet-stream |
| Archive | ps | application/postscript |
| Archive | sqlite | application/x-sqlite3 |
| Archive | nes | application/x-nintendo-nes-rom |
| Archive | crx | application/x-google-chrome-extension |
| Archive | cab | application/vnd.ms-cab-compressed |
| Archive | deb | application/x-deb |
| Archive | ar | application/x-unix-archive |
| Archive | Z | application/x-compress |
| Archive | lz | application/x-lzip |
| Archive | rpm | application/x-rpm |
| Archive | elf | application/x-executable |
| Archive | dcm | application/dicom |
| Document | doc | application/msword |
| Document | docx | application/vnd.openxmlformats-officedocument.wordprocessingml.document |
| Document | xls | application/vnd.ms-excel |
| Document | xlsx | application/vnd.openxmlformats-officedocument.spreadsheetml.sheet |
| Document | ppt | application/vnd.ms-powerpoint |
| Document | pptx | application/vnd.openxmlformats-officedocument.presentationml.presentation |
| Font | woff | application/font-woff |
| Font | woff2 | application/font-woff |
| Font | ttf | application/font-sfnt |
| Font | otf | application/font-sfnt |
| Application | wasm | application/wasm |