ABIExample.sol

pragma solidity ^0.4.24;
pragma experimental ABIEncoderV2;
 
 
contract ABIExample {
 
  enum Permission { ReadOnly, Write, Admin }
 
  struct User {
    uint256 id;
    Permission permission;
  }
 
  User[] users;
 
  constructor() public {
    users.push(User(uint256(111), Permission.Admin));
    users.push(User(uint256(222), Permission.Write));
    users.push(User(uint256(333), Permission.ReadOnly));
  }
 
  function getUsers() public constant returns (User[]) {
    return users;
  }
 
  // New method to encode users before returning as bytes.
  function getUsersBytes() public constant returns (bytes) { // Change return type to bytes.
    return abi.encode(users); // Encode prior to return.
  }
 
}

run_example.js

// Imports
const ethers       = require('ethers');
const solc         = require('solc');
const ganache      = require("ganache-cli");

// Provider / Signer setup.
const providers    = ethers.providers;
const web3Provider = new providers.Web3Provider(ganache.provider({ gasLimit: 6e6 }));
const signer       = web3Provider.getSigner();

let contractCode = `pragma solidity ^0.4.24;
pragma experimental ABIEncoderV2;


contract ABIExample {

  enum Permission { ReadOnly, Write, Admin }

  struct User {
    uint256 id;
    Permission permission;
  }

  User[] users;

  constructor() public {
    users.push(User(uint256(111), Permission.Admin));
    users.push(User(uint256(222), Permission.Write));
    users.push(User(uint256(333), Permission.ReadOnly));
  }

  function getUsers() public constant returns (User[]) {
    return users;
  }

  // New method to encode users before returning as bytes.
  function getUsersBytes() public constant returns (bytes) { // Change return type to bytes.
    return abi.encode(users); // Encode prior to return.
  }

}`

// Recompile
let compiledContract = solc.compile(contractCode);

// Prepare deployment overwriting interface and bytecode.
let interface         = compiledContract.contracts[':ABIExample'].interface;
let bytecode          = compiledContract.contracts[':ABIExample'].bytecode;
let deployTransaction = ethers.Contract.getDeployTransaction('0x' + bytecode, interface);
let sendPromise       = signer.sendTransaction(Object.assign(deployTransaction, { gas: 6e6 }));

// Deploy contract.
let transactionReceipt;
let userArray;
let userBytesArray;

sendPromise.then(res => {
    web3Provider.getTransactionReceipt(res.hash).then(res => {
        transactionReceipt = res;

        // New JS contract interface.
        ABIExample = new ethers.Contract(transactionReceipt.contractAddress, interface, signer);

        ABIExample.getUsers().then(res => {
          // Log result of calling the contract's `get()` function.
          userArray = res;
          console.log(`userArray -> `);
          console.log(userArray);
          
          
        });

        ABIExample.getUsersBytes().then(res => {

            // Log result of calling the contract's `getUsersBytes()` function.
            userBytesArray = res;
            console.log(`userBytesArray -> `);
            console.log(userBytesArray);
        });
    });
});