fix(node): stream has a memory leak, use event emitter instead

I think the stream is retaining all of the coins it's fired, until it closes, which never happens.
An event emitter is more in line with the intention

packages/bitcore-node/src/services/event.ts

@@ -1,16 +1,16 @@
+import { EventEmitter } from "events";
 import logger from '../logger';
 import { StorageService } from './storage';
 import { LoggifyClass } from '../decorators/Loggify';
 import { EventStorage, IEvent, EventModel } from '../models/events';
-import { PassThrough } from 'stream';
 import { Storage } from './storage';
 import { Config, ConfigService } from './config';
 
 @LoggifyClass
 export class EventService {
- txStream = new PassThrough({ objectMode: true });
- blockStream = new PassThrough({ objectMode: true });
- addressCoinStream = new PassThrough({ objectMode: true });
+ txEvent = new EventEmitter();
+ blockEvent = new EventEmitter();
+ addressCoinEvent = new EventEmitter();
  storageService: StorageService;
  configService: ConfigService;
  eventModel: EventModel;
@@ -57,7 +57,7 @@ export class EventService {
  const txEvent = await txCursor.next();
  if (txEvent) {
  const tx = <IEvent.TxEvent>txEvent.payload;
- this.txStream.write(tx);
+ this.txEvent.emit('tx', tx);
  lastTxUpdate = new Date();
  }
  }
@@ -73,7 +73,7 @@ export class EventService {
  const blockEvent = await blockCursor.next();
  if (blockEvent) {
  const block = <IEvent.BlockEvent>blockEvent.payload;
- this.blockStream.write(block);
+ this.blockEvent.emit('block', block);
  lastBlockUpdate = new Date();
  }
  }
@@ -89,7 +89,7 @@ export class EventService {
  const addressTx = await addressTxCursor.next();
  if (addressTx) {
  const addressCoin = <IEvent.CoinEvent>addressTx.payload;
- this.addressCoinStream.write(addressCoin);
+ this.addressCoinEvent.emit('coin', addressCoin);
  lastAddressTxUpdate = new Date();
  }
  }

packages/bitcore-node/src/services/socket.ts

@@ -66,22 +66,22 @@ export class SocketService {
  }
 
  async wireup() {
- this.eventService.txStream.on('data', (tx: IEvent.TxEvent) => {
+ this.eventService.txEvent.on('tx', (tx: IEvent.TxEvent) => {
  if (this.io) {
  const { chain, network } = tx;
  const sanitizedTx = SanitizeWallet(tx);
  this.io.sockets.in(`/${chain}/${network}/inv`).emit('tx', sanitizedTx);
  }
  });
 
- this.eventService.blockStream.on('data', (block: IEvent.BlockEvent) => {
+ this.eventService.blockEvent.on('block', (block: IEvent.BlockEvent) => {
  if (this.io) {
  const { chain, network } = block;
  this.io.sockets.in(`/${chain}/${network}/inv`).emit('block', block);
  }
  });
 
- this.eventService.addressCoinStream.on('data', (addressCoin: IEvent.CoinEvent) => {
+ this.eventService.addressCoinEvent.on('coin', (addressCoin: IEvent.CoinEvent) => {
  if (this.io) {
  const { coin, address } = addressCoin;
  const { chain, network } = coin;