Limiting selectable file types

Video introduction

The default document picker allows any file to be selected (except virtual files). Use the type parameter of pick() to restrict selectable file types.

• On iOS, these are Apple Uniform Type Identifiers.

• On Android, these are MIME types such as text/plain or partial MIME types such as image/*. See common MIME types or a more comprehensive IANA Media Types listing.

Figuring out the correct MIME type or UTType identifier for a file type can be a bit of a hassle. To make it easier, the module exports the isKnownType utility and several predefined file types that you can use.

warning

On Android, some Document Providers (this seems to be a problem especially in Asia) ignore the type parameter and allow any file to be selected. This is a problem with the Document Provider, not this module.

To detect this case, check the hasRequestedType field and handle the situation in your app.

Limiting selectable file types to pdf and docx

import { pick, types } from '@react-native-documents/picker'

return (
  <Button
    title="import multiple docx or pdf files"
    onPress={() => {
      pick({
        allowMultiSelection: true,
        type: [types.pdf, types.docx],
      })
        .then((res) => {
          const allFilesArePdfOrDocx = res.every((file) => file.hasRequestedType)
          if (!allFilesArePdfOrDocx) {
            // tell the user they selected a file that is not a pdf or docx
          }
          addResult(res)
        })
        .catch(handleError)
    }}
  />
)

isKnownType

isKnownType is a handy utility function that given one of:

• UTType identifier string
• MIME type string
• File extension string

returns the corresponding MIME type, file extension, and UTType identifier.

import { isKnownType } from '@react-native-documents/picker'

const { isKnown, mime, preferredFilenameExtension } = isKnownType({
  kind: 'extension',
  value: 'pdf',
})

If you know the file extension (or the MIME, or the UTType), then use isKnownType to find the corresponding MIME type for Android or UTType for iOS. Then pass the result to the type parameter of pick.

note

Prefer using the iOS implementation of isKnownType. On Android, the function does not provide UTType identifier information (as it's an iOS-only concept) and the results may not be as accurate.

Different devices, based on the installed apps, may recognize different file types.

Predefined File Types

These are the most common file types, and are available in the types export. See the usage example above.

import { types } from '@react-native-documents/picker'

• types.allFiles: All document types, on Android this is */*, on iOS it's public.item
• types.images: All image types
• types.plainText: Plain text files
• types.audio: All audio types
• types.pdf
• types.zip
• types.csv
• types.doc
• types.docx
• types.ppt
• types.pptx
• types.xls
• types.xlsx