node.js mysql query seems not to wait

Question

I hope, you can help me with my async-await-issue..

I want so search in several databases, concat the results and return them as a json via express. It seems, that my "await db.query("SELECT..")" does not wait till the result arrived.

This is my DummySearchModule.js

const mysql = require('mysql');

const SearchModuleInterface = require('./SearchModuleInterface');
const SearchResult = require('./SearchResult');

class DummySearchModule extends SearchModuleInterface {
    constructor() {
        super();

        var outer = this;
        this.db = mysql.createConnection({
            host: "127.0.0.1",
            user: "db_user",
            password: "db_pw",
            database: "global_search"
          });

          this.db.connect(function(err) {
            if (err) throw err;
            console.log("Connected!");
        });
    }

    
    async search(search_term) {
        var resultSet = [];
        const dbResult = await this.db.query(`SELECT id, title, content, description FROM demo_entries`);
        console.log("dbResult from db:");
        console.log(dbResult[0]);
        for(var element in dbResult[0]) {
            var result = new SearchResult();
            result.title = element.title;
            result.description = element.description;
            result.content = element.content;
            result.date = Date.now();
            
            console.log("title: " + element.title + ":: content: " + element.content);
            resultSet.push(result);
        }

        console.log(resultSet);
        return resultSet;
    };
   
}

module.exports = DummySearchModule;

and this is my frontend-server.js

const express = require("express");
var dateFormat = require('dateformat');

const dummysearchmodule = require('./objects/DummySearchModule');

const server_port = 3000;
const search_modules = [new dummysearchmodule()];
[...]

    app.get("/search/:search_term", (req, res, next) => {
    search_modules.forEach(function(item, index, array) {
        var results = item.search(req.params.search_term);
       resultSet = searchInEveryModuleWithSearchterm(search_term); 
    });

    res.json(resultSet);
});

And this is my output, and i don't know, why I get this..

Connected!
dbResult from db:
<ref *1> Query {
  _events: [Object: null prototype] {
    error: [Function (anonymous)],
    packet: [Function (anonymous)],
    timeout: [Function (anonymous)],
    end: [Function (anonymous)]
  },
  _eventsCount: 4,
  _maxListeners: undefined,
  _callback: [Function (anonymous)],
  _callSite: Error
      at Protocol._enqueue (\frontend\node_modules\mysql\lib\protocol\Protocol.js:144:48)
      at Connection.query (\frontend\node_modules\mysql\lib\Connection.js:198:25)
      at DummySearchModule.search (\frontend\objects\DummySearchModule.js:27:40)
      at \frontend\frontend-server.js:25:31
      at Array.forEach (<anonymous>)
      at searchEveryModuleForResultWithSearchTerm (\frontend\frontend-server.js:24:20)
      at \frontend\frontend-server.js:17:20
      at Layer.handle [as handle_request] (\frontend\node_modules\express\lib\router\layer.js:95:5)
      at next (\frontend\node_modules\express\lib\router\route.js:137:13)
      at Route.dispatch (\frontend\node_modules\express\lib\router\route.js:112:3),
  _ended: false,
  _timeout: undefined,
  _timer: Timer { _object: [Circular *1], _timeout: null },
  sql: 'SELECT id, title, content, description FROM demo_entries',
  values: undefined,
  typeCast: true,
  nestTables: false,
  _resultSet: null,
  _results: [],
  _fields: [],
  _index: 0,
  _loadError: null,
  _connection: <ref *2> Connection {
    _events: [Object: null prototype] {},
    _eventsCount: 0,
    _maxListeners: undefined,
    config: ConnectionConfig {
      host: '127.0.0.1',
      port: 3306,
      localAddress: undefined,
      socketPath: undefined,
      user: 'remote_user',
      password: 'global_search',
      database: 'global_search',
      connectTimeout: 10000,
      insecureAuth: false,
      supportBigNumbers: false,
      bigNumberStrings: false,
      dateStrings: false,
      debug: undefined,
      trace: true,
      stringifyObjects: false,
      timezone: 'local',
      flags: '',
      queryFormat: undefined,
      pool: undefined,
      ssl: false,
      localInfile: true,
      multipleStatements: false,
      typeCast: true,
      maxPacketSize: 0,
      charsetNumber: 33,
      clientFlags: 455631,
      protocol41: true
    },
    _socket: Socket {
      connecting: false,
      _hadError: false,
      _parent: null,
      _host: null,
      _readableState: [ReadableState],
      [Symbol(kSetNoDelay)]: false,
      [Symbol(lastWriteQueueSize)]: 0,
      [Symbol(timeout)]: Timeout {
        _idleTimeout: -1,
        _idlePrev: null,
        _idleNext: null,
        _idleStart: 174,
        _onTimeout: null,
        _timerArgs: undefined,
        _repeat: null,
      [Symbol(kCapture)]: false,
      [Symbol(kBytesRead)]: 0,
      [Symbol(kBytesWritten)]: 0
    },
    _protocol: Protocol {
      _events: [Object: null prototype],
      _eventsCount: 7,
      _maxListeners: undefined,
      readable: true,
      writable: true,
      _fatalError: null,
      _quitSequence: null,
      _handshake: true,
      _handshaked: true,
      _ended: false,
      _destroyed: false,
      _queue: [Array],
      _handshakeInitializationPacket: [HandshakeInitializationPacket],
      _parser: [Parser],
      [Symbol(kCapture)]: false
    },
    _connectCalled: true,
    state: 'authenticated',
    threadId: 23,
    [Symbol(kCapture)]: false
  },
  [Symbol(kCapture)]: false
}

If I log the output in the query function query("SELECT..", (err, res, fields) => console.log(res);} , I get the correct output. My mysql-server is running in a docker-container.

Does anyone have any clue, o how I can archive my goal? Thanks a lot!!!

Answer 1

My understanding is that mysql does not support await/async out-of-the-box. You can try mysql2 instead (it is almost completely compatible with mysql API), for example it has a promise wrapper which you can use and have all these await/async