Question

I am fairly certain this is a ten penny closure question. But having read a few articles on closures, I still cannot get this to work.

character is always returned as ‘Z’. character is also a global variable.

I need “render” to remember the character in the loop:

populateList: function()
{           
    var render = function(tx, result)
    {   
        console.log(character);

        for (var i = 0; i < result.rows.length; i++) 
        {
            var contact = result.rows.item(i);
            console.log(contact.Name);
        }
    }

    var str = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    for(var i = 0; i < str.length; i++)
    {
        var nextChar = str.charAt(i);
        database.open();
        var sql = "SELECT Name FROM Contact WHERE Name LIKE \'" + nextChar + "%\' ORDER BY Name";
        database.query(sql, render);
    }
}

Answer 1

var render = function(character)
{
    return function(tx, result)
    {
        console.log(character);

        for (var i = 0; i < result.rows.length; i++) 
        {
            var contact = result.rows.item(i);
            console.log(contact.Name);
        }
    }
}

Usage:

database.query(sql, render(nextChar));

Edit:

Also, asawyer is correct in his comment above — assuming you are using node-mysql, it has support for parameterized queries:

database.query("SELECT * FROM foo WHERE bar = ?", [ 1 ]);

Use that and save yourself some trouble!