mysql query on node.js is giving me a object object result

Question

Hi

I have this query on node.js. This is my server side file:

    function doquery(select,from,where,value) {
     var con = mysql.createConnection({
          host: "localhost",
          database: "db545",
          user: "root",
          password: "mypass"
        });
        
     return con.query("SELECT " + select + " FROM " + from + " WHERE " + where + value);
    };
    
   io.on('connection', (socket) => {
      // when the client emits 'add user', this listens and executes
      socket.on('add user', (username) => {
        dispname = doquery('name','members','member_id','1');

but the variable dispname is resulting in [object object] but since this is server side Im not getting any errors so I cant debug it. What is wrong?

Thank you.

seems that everything is fine, it returns the result object (handler) — Flash Thunder
– Flash Thunder, Commented Sep 18, 2021 at 17:10
"so I cant debug it" << you could attach a debugger to your process. You use a locl debugger to debug a remote process by forwarding port 9229 from your server via SSH, sending SIGUSR1 to the process to enable debug mode (or enable it from the start by passing --inspect to node) and then connecting with the Chrome devtools' "node" button which will appear in the toolbar at that point - or VSCode's debugger. In VSCode you can even use the remote mode (bottom-left corner) to do the whole thing with a nice interface. This will allow you to debug code running on a server. — CherryDT
– CherryDT, Commented Sep 18, 2021 at 17:13
Also I think the issue is that you are getting a promise returned and you don't await it. (It's not clear because you didn't show which mysql package you are using exactly, there are multiple.) — CherryDT
– CherryDT, Commented Sep 18, 2021 at 17:15
but do what? con.query doesn't return the result... it has a callback to return the result, you are just doing it wrong, read the documentation... con.query(your_query, function (error, results, fields) {...} — Flash Thunder
– Flash Thunder, Commented Sep 18, 2021 at 17:16

Mureinik · Accepted Answer · 2021-09-18 17:12:33Z

2

[object Object] is the default string representation of an object. If you want to properly debug the result, you could serialize it to JSON:

console.log(JSON.stringify(dispname));

Side note:
By concatenating strings to your SQL query like that you're making the application vulnerable to SQL Injection attacks. I strongly recommend you look into prepared statements instead.

answered Sep 18, 2021 at 17:12

Mureinik

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3 Comments

Cain Nuke Over a year ago

I cant log it into the console because its server side. Also, I tried JSON.stringify(dispname) but my app crashes. I get a 500 error.

CherryDT Over a year ago

Why can't you look at your server's console then?

Cain Nuke Over a year ago

I did but Im getting nothing.

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