Gets all transactions given an account recursively - NEM2-SDK + rxjs

getAllTransactions.ts

import {AccountHttp, NetworkType, PublicAccount, QueryParams} from "nem2-sdk";
import {concatMap, expand, toArray} from "rxjs/operators";
import {EMPTY} from 'rxjs'

const nodeUrl = 'http://localhost:3000';
const accountHttp = new AccountHttp(nodeUrl);

const pageSize = 100;
const allTransactions = true;

const publicKey = process.env.PUBLIC_KEY as string; //Replace with your public key
const publicAccount = PublicAccount
    .createFromPublicKey(publicKey, NetworkType.MIJIN_TEST);

accountHttp
    .transactions(publicAccount, new QueryParams(pageSize, null))
    .pipe(
        expand( (transactions) => transactions.length >= pageSize && allTransactions
            ? accountHttp.transactions(publicAccount, new QueryParams(pageSize, transactions[transactions.length - 1].transactionInfo.id))
            : EMPTY),
        concatMap(transactions => transactions),
        toArray()
    )
    .subscribe(transactions => {
        console.log(transactions);
        console.log(transactions.length);
    },
    err => console.log(err));