@uppy/utils/src/getFileType.ts

Shared utility functions for Uppy Core and plugins maintained by the Uppy team.

import getFileNameAndExtension from './getFileNameAndExtension.js'
import mimeTypes from './mimeTypes.js'

export default function getFileType(file: {
  type?: string
  name?: string
}): string {
  if (file.type) return file.type

  const fileExtension =
    file.name ?
      getFileNameAndExtension(file.name).extension?.toLowerCase()
    : null
  if (fileExtension && fileExtension in mimeTypes) {
    // else, see if we can map extension to a mime type
    return mimeTypes[fileExtension as keyof typeof mimeTypes]
  }
  // if all fails, fall back to a generic byte stream type
  return 'application/octet-stream'
}