session-desktop/ts/types/MIME.ts

export type MIMEType = string & { _mimeTypeBrand: any };

export const isJPEG = (value: MIMEType): boolean => value === 'image/jpeg';
export const isImage = (value: MIMEType): boolean => value.startsWith('image/');
export const isVideo = (value: MIMEType): boolean => value.startsWith('video/');
export const isAudio = (value: MIMEType): boolean => value.startsWith('audio/');

export const APPLICATION_OCTET_STREAM = 'application/octet-stream' as MIMEType;