📓 Paginator

Introduction

The Paginator library provides pagination functionality for arrays and OpenZeppelin's Enumerable Sets. This makes it possible to retrieve specific portions of data, making it useful for managing large datasets efficiently.

A smart contract possesses limitless storage capacity, allowing for the storage of extensive data. However, due to the finite gas limit and execution time constraints, retrieving such voluminous data in a single request is often impossible. Pagination serves as a practical tool, facilitating the retrieval of information through a series of smaller requests.

Functions

To use the Paginator library, you need to import it.

import "@solarity/solidity-lib/libs/arrays/Paginator.sol";

And optionally bind it to the type with the using statement.

using Paginator for *;

part

function part(
    uint256[] storage arr,
    uint256 offset_,
    uint256 limit_
) internal view returns (uint256[] memory list_);

function part(
    address[] storage arr,
    uint256 offset_,
    uint256 limit_
) internal view returns (address[] memory list_);

function part(
    bytes32[] storage arr,
    uint256 offset_,
    uint256 limit_
) internal view returns (bytes32[] memory list_);

function part(
    EnumerableSet.UintSet storage arr,
    uint256 offset_,
    uint256 limit_
) internal view returns (uint256[] memory list_);

function part(
    EnumerableSet.AddressSet storage arr,
    uint256 offset_,
    uint256 limit_
) internal view returns (address[] memory list_);

function part(
    EnumerableSet.Bytes32Set storage arr,
    uint256 offset_,
    uint256 limit_
) internal view returns (bytes32[] memory list_);

function part(
    StringSet.Set storage arr,
    uint256 offset_,
    uint256 limit_
) internal view returns (string[] memory list_);

Description

This function returns a portion of an arr, starting from the offset_ index and including limit_ elements. A parameter set is always a storage array, whereas a result list_ is a memory array.

Time complexity

Linear, depends on a limit_.

Example

EnumerableSet.UintSet public nums;
nums.add(1); 
nums.add(2); 
nums.add(3); 
nums.add(4); 

nums.part(0, 99); // [1, 2, 3, 4]
nums.part(2, 99); // [3, 4]
nums.part(1, 1);  // [2]