Iterating over an array of SQL data

[95040343]

Hello,

I am trying to make a login system with WebSQL. The sign up works. However, I want to make a function to see if I can see the usernames in an array. This is my code (I have a column for name and password):

var db = openDatabase('personDB', '1.0', 'the data of people', 2*1024*1024);
var exists=[];
db.transaction(function (tx) {
  tx.executeSql('SELECT * FROM people', [], function (tx, results) {
    var len = results.rows.length, i;
    for (i = 0; i < len; i++) {
      exists.push(results.rows.item(i).username);
    }
  });
});
return exists;

When I try it in a snap block, it doesn't report anything. Well, it reports something, but it reports a blank and empty array. However, when I try to do it in console, it works perfectly. Is there something I am doing wrong?

I'd appreciate it if I could get a quick response, because this is part of a project that is due tomorrow.

[dardoro]

@95040343

return exists;

...
return new List( exists);

[95040343]

Sorry, I tried it but the list has no elements. I think the problem lies in the for loop's body, because it does not work however I do it.

[95040343]

It works in the console. It returns an array with the data, but when I do it in snap, it just reports an empty array. Do you know if something is wrong?

[18001767679]

@95040343

db.transaction(function (tx) {
  tx.executeSql('SELECT * FROM people', [], function (tx, results) {
    var len = results.rows.length, i;
    for (i = 0; i < len; i++) {
      exists.push(results.rows.item(i).username);
    }
  });
});

Async closure!!!

[programmer_user]

Why are you using Web SQL? It's deprecated and has never been supported in Firefox.
The reason why it's not reporting is because you are using a callback. What you can do is report a function that resolves to a variable that contains the results (null initially) and wait until that variable is truthy.

[18001767679]

@18001767679

Async closure

right?

[programmer_user]

You didn't explain why that was the problem.

[95040343]

It's fine, I realized that WebSQL was deprecated, so I just used LocalStorage. I know, not the best solution, but best I have right now.