Question

Hey all I’ve just been fooling around with the HTML5 Database API and I’m having trouble return the result from a function. Here is what I have.

var list = GetScenarios();

GetScenarios: function()
{

var scenarios;

// get all the scenarios
conn.transaction(function(_t) {

_t.executeSql('SELECT * FROM scenarios', [], function(_tr, _result) {

        scenarios = _result.rows;

    });
});

return scenarios;

}

I manage to get the rows from the db but the rows wont assign to the variable scenarios. I know its a scope thing but I can’t think how to return the result from the GetScenatios function.

When I log _result.rows I have the data there but scenario is always undefined;

Any thoughts?

Here is how my js file is setup.

window.MyExtension = (function() 
{

    return ({

    OtherMethod: function() {   


        var list = window.MyExtension.GetScenarios();

    },

    GetScenarios: function() {

         ...see above

    }

}());

Answer 1

It looks like you are trying to return code from an asynchronous request as though it were synchronous. You need to add a callback parameter to GetScenarios():

function GetScenarios(callback) {
    conn.transaction(function(_t) {
        _t.executeSql('...', [], function(_tr, _result) {
            callback(_result.rows);
        });
    });
}

And change your calling code from:

var list = GetScenarios();
// do something with list

To, this:

GetScenarios(function (list) {
    // do something with list
});