["photos/1.jpg", "photos/2.jpg", "photos/sub/3.png", "file.jpg"]

=>

[{
  name: 'photos',
  type: 'folder',
  children: [
    {
      name: 'sub',
      type: 'folder',
      children: [
        { name: '3', type: 'file' }
      ]
    },
    { name: '1.jpg', type: 'file' },
    { name: '2.jpg', type: 'file' }
},
{ name: 'file.jpg', type: 'file' }]