Handling permissions in Expo

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expo/handling-permissions-expo.md
expo

Jul 14, 2020

expo install expo-permissions

You can check if a permission is granted with Permissions.getAsync(...permissionTypes) and ask for a permission with Permissions.askAsync(...types)
Both return a Promise with has status and expires as well as details about scope
The status is usually granted or denied. It could also be undetermined in case of Permissions.NOTIFICATIONS for iOS, as iOS does not disambiguate undetermined from denied
Make sure you're basing your logic on granted and !granted to account for cases like undetermined that only happen on iOS and only for some permissions
on iOS remote notifications only show if allowsSound, allowsAlert or allowsBadge is set.

There are about a dozen permission types
- NOTIFICATIONS
- USER_FACING_NOTIFICATIONS
- LOCATION
- CAMERA
- AUDIO_RECORDING
- CONTACTS
- CAMERA_ROLL
- CALENDAR
- REMINDERS
- SYSTEM_BRIGHTNESS
- MOTION

async function alertIfRemoteNotificationsDisabledAsync() {
  const { status } = await Permissions.getAsync(Permissions.NOTIFICATIONS)
  if (status !== 'granted') {
    alert('Hey! You might want to enable notifications for my app, they are good.')
  }
}

async function checkMultiPermissions() {
  const { status, expires, permissions } = await Permissions.getAsync(Permissions.CALENDAR, Permissions.CONTACTS)
  if (status !== 'granted') {
    alert('Hey! You heve not enabled selected permissions')
  }
}

Here's an example asking for permissions for push notifications..

const askPermissions = async () => {
  // See if app already has permission
  const { status: existingStatus } = await Permissions.getAsync(Permissions.NOTIFICATIONS)
  let finalStatus = existingStatus

  // No existing permisson, ask for it
  if (existingStatus !== 'granted') {
    const { status } = await Permissions.askAsync(Permissions.NOTIFICATIONS)
    finalStatus = status
  }

  // Permission denied
  if (finalStatus !== 'granted') {
    return false
  }

  return true
}

Handling permissions in Expo

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