#Function to Get Permissions on a particular on List, Folder or List Item
  Function Get-PnPPermissions([Microsoft.SharePoint.Client.SecurableObject]$Object)
  {
      $ParentUrl = ""
      $Id = ""
      #Determine the type of the object     
      Switch($Object.TypedObject.ToString())
      {
          "Microsoft.SharePoint.Client.ListItem"
          {
              If($Object.FileSystemObjectType -eq "Folder")
              {
                  $ObjectType = "Folder"
                  $Id = $Object.Id
                  #Get the URL of the Folder
                  $Folder = Get-PnPProperty -ClientObject $Object -Property Folder
                  $ObjectTitle = $Object.Folder.Name
                  $ObjectURL = $Object.Folder.ServerRelativeUrl
                  $ParentUrl = (Split-Path $ObjectURL -Parent).Replace("\","/")
              }
              Else #File or List Item
              {
                  #Get the URL of the Object
                  Get-PnPProperty -ClientObject $Object -Property File, ParentList
                  If($Object.File.Name -ne $Null)
                  {
                      $ObjectType = "File"
                      $Id = $Object.Id
                      $ObjectTitle = $Object.File.Name
                      $ObjectURL = $Object.File.ServerRelativeUrl
                      $ParentUrl = (Split-Path $ObjectURL -Parent).Replace("\","/")
                  }
                  else
                  {
                      $ObjectType = "List Item"
                      $Id = $Object.Id
                      $ObjectTitle = $Object["Title"]
                      #Get the URL of the List Item
                      $DefaultDisplayFormUrl = Get-PnPProperty -ClientObject $Object.ParentList -Property DefaultDisplayFormUrl                    
                      $ObjectURL = $("{0}?ID={1}" -f $DefaultDisplayFormUrl,$Object.ID)
                  }
              }
          }
          Default
          {
              $ObjectType = "List or Library"
              $ObjectTitle = $Object.Title
              $Id = $Object.Id
              #Get the URL of the List or Library
              $RootFolder = Get-PnPProperty -ClientObject $Object -Property RootFolder    
              $ObjectURL = $RootFolder.ServerRelativeUrl
          }
      }
            
      #Get permissions assigned to the object
      Get-PnPProperty -ClientObject $Object -Property HasUniqueRoleAssignments, RoleAssignments
          
      #Check if Object has unique permissions
      $HasUniquePermissions = $Object.HasUniqueRoleAssignments
              
      #Loop through each permission assigned and extract details
      $PermissionCollection = @()
      Foreach($RoleAssignment in $Object.RoleAssignments)
      {
          #Get the Permission Levels assigned and Member
          Get-PnPProperty -ClientObject $RoleAssignment -Property RoleDefinitionBindings, Member
          
          #Get the Principal Type: User, SP Group, AD Group
          $PermissionType = $RoleAssignment.Member.PrincipalType
             
          #Get the Permission Levels assigned
          $PermissionLevels = $RoleAssignment.RoleDefinitionBindings | Select -ExpandProperty Name
          
          #Remove Limited Access
          $PermissionLevels = ($PermissionLevels | Where { $_ -ne "Limited Access"}) -join ","
          
          #Leave Principals with no Permissions
          If($PermissionLevels.Length -eq 0) {Continue}
          
          #Get SharePoint group members
          If($PermissionType -eq "SharePointGroup")
          {
              #Get Group Members
              $GroupMembers = Get-PnPGroupMember -Identity $RoleAssignment.Member.LoginName
                          
              #Leave Empty Groups
              If($GroupMembers.count -eq 0){Continue}
              $GroupUsers = ($GroupMembers | Select -ExpandProperty Title) -join "; "
          
              #Add the Data to Object
              $Permissions = New-Object PSObject
              $Permissions | Add-Member NoteProperty ObjectId($Id) 
              $Permissions | Add-Member NoteProperty Object($ObjectType)            
              $Permissions | Add-Member NoteProperty Title($ObjectTitle)
              $Permissions | Add-Member NoteProperty URL($ObjectURL)
              $Permissions | Add-Member NoteProperty ParentURL($ParentURL)
              $Permissions | Add-Member NoteProperty HasUniquePermissions($HasUniquePermissions)
              $Permissions | Add-Member NoteProperty Users($GroupUsers)
              $Permissions | Add-Member NoteProperty Type($PermissionType)
              $Permissions | Add-Member NoteProperty Permissions($PermissionLevels)
              $Permissions | Add-Member NoteProperty GrantedThrough("SharePoint Group: $($RoleAssignment.Member.LoginName)")
              $PermissionCollection += $Permissions
          }
          Else
          {
              #Add the Data to Object
              $Permissions = New-Object PSObject
              $Permissions | Add-Member NoteProperty ObjectId($Id)
              $Permissions | Add-Member NoteProperty Object($ObjectType)             
              $Permissions | Add-Member NoteProperty Title($ObjectTitle)
              $Permissions | Add-Member NoteProperty URL($ObjectURL)
              $Permissions | Add-Member NoteProperty ParentURL($ParentURL)
              $Permissions | Add-Member NoteProperty HasUniquePermissions($HasUniquePermissions)
              $Permissions | Add-Member NoteProperty Users($RoleAssignment.Member.Title)
              $Permissions | Add-Member NoteProperty Type($PermissionType)
              $Permissions | Add-Member NoteProperty Permissions($PermissionLevels)
              $Permissions | Add-Member NoteProperty GrantedThrough("Direct Permissions")
              $PermissionCollection += $Permissions
          }
      }
      return $PermissionCollection
  }
    
    
    
    
 function Check-Permission
 {
   param(
      $DocumentLib,
      $FolderName
   )
   $folderPermission = @()
   #Get the Context
   $Context = Get-PnPContext
   $List = Get-PnpList -Identity $DocumentLib -Includes RoleAssignments
    
   $folderPermission += Get-PnPPermissions $List
    
   if($FolderName -eq "")
   {
     $ListItems = Get-PnPListItem -List $List -PageSize 500 
   }
   else
   {
     $ParentItem = Get-PnpListItem -List "Shared Documents" | Where-Object {$_.FieldValues.FileRef -eq "/$($DocumentLib)/$FolderName"}
     $folderPermission += Get-PnPPermissions -Object $ParentItem
     $ListItems = Get-PnPListItem -List $List -PageSize 500 -FolderServerRelativeUrl "/$($DocumentLib)/$FolderName"
   }
    
   ForEach($ListItem in $ListItems)
   {
       $folderPermission += Get-PnPPermissions -Object $ListItem
   }    
   $FilesOrFolderWithUP = $folderPermission | Where-Object {$_.HasUniquePermissions -eq $true}
    
   $GroupedObject = $FilesOrFolderWithUP | Group-Object -Property "URL"
    
   foreach($GroupObj in $GroupedObject)
   {
    if($GroupObj.Group[0].ParentUrl -ne $null -and $GroupObj.Group[0].ParentUrl -ne "")
    {
     $ParentObject = $folderPermission | Where-Object {$_.URL -eq $GroupObj.Group[0].ParentUrl} | Group-Object -Property "URL"
     $Result = Compare-Object -ReferenceObject $ParentObject.Group -DifferenceObject $GroupObj.Group
     if($Result -eq $null)
     {
       $GroupObj.Group[0].Url       
       #Set-PnPListItemPermission -List $GroupObj.Group[0].Url -Identity $GroupObj.Group[0].Url -InheritPermissions
       $Item = Get-PnPListItem -List "Shared Documents" | Where-Object {$_.FieldValues.FileRef -eq "$($GroupObj.Group[0].Url)"}
       #sharepoint online delete unique permissions powershell
       $Item.ResetRoleInheritance()
       $Item.Update()
       $Context.ExecuteQuery()
       Write-Host "The $($GroupObj.Group[0].Url) unique permission has been stopped" -ForegroundColor Green 
     }
    }
   }
 }
    
 $SiteURL = "https://domain.sharepoint.com"
    
 $DocumentLibrary = "Document Name"
    
 $FolderName = "Test"
    
 #Connect to SharePoint Online
 Connect-PnPOnline $SiteURL -UseWebLogin
    
 Check-Permission -DocumentLib "$($DocumentLibrary)" -FolderName $($FolderName)