Plugin that provides pagination functionality for relation modules.

This plugin adds pagination functions that return Drops.Relation.Loaded structs containing both the paginated data and metadata for navigation.

Functions Added

• page/1 - Load a specific page with default per_page
• page/2 - Load a specific page with custom per_page
• per_page/1 - Set per_page for subsequent pagination
• per_page/2 - Set per_page on an existing relation

Examples

iex> # Basic pagination - first page with default per_page
iex> loaded = MyApp.Users.page(1)
iex> loaded.meta.pagination.page
1
iex> loaded.meta.pagination.per_page
20
iex> loaded.meta.pagination.total_count
3
iex> loaded.meta.pagination.total_pages
1
iex> loaded.meta.pagination.has_next
false
iex> loaded.meta.pagination.has_prev
false
iex> length(loaded.data)
3

iex> # Pagination with custom per_page
iex> loaded = MyApp.Users.page(1, 2)
iex> loaded.meta.pagination.page
1
iex> loaded.meta.pagination.per_page
2
iex> loaded.meta.pagination.total_count
3
iex> loaded.meta.pagination.total_pages
2
iex> loaded.meta.pagination.has_next
true
iex> loaded.meta.pagination.has_prev
false
iex> length(loaded.data)
2

iex> # Second page
iex> loaded = MyApp.Users.page(2, 2)
iex> loaded.meta.pagination.page
2
iex> loaded.meta.pagination.per_page
2
iex> loaded.meta.pagination.total_count
3
iex> loaded.meta.pagination.total_pages
2
iex> loaded.meta.pagination.has_next
false
iex> loaded.meta.pagination.has_prev
true
iex> length(loaded.data)
1

iex> # Set per_page first, then paginate
iex> relation = MyApp.Users.per_page(2)
iex> loaded = MyApp.Users.page(relation, 1)
iex> loaded.meta.pagination.per_page
2
iex> length(loaded.data)
2

iex> # Access data using Enumerable protocol
iex> loaded = MyApp.Users.page(1, 2)
iex> users = Enum.to_list(loaded)
iex> length(users)
2
iex> first_user = Enum.at(loaded, 0)
iex> first_user.name
"John Doe"
iex> user_names = Enum.map(loaded, & &1.name)
iex> length(user_names)
2

Configuration

The default per_page value can be configured:

config :my_app, :drops,
  relation: [
    default_per_page: 25
  ]

If not configured, the default per_page is 20.