I'm trying to use sqlite3 in an expressjs app (nodejs)

I want to create a Function that returns all the results from a select statement. This function will be called by a route that

var queryGetAll = 'SELECT id, title, description, modified, lat, lng, zoom FROM maps';
function Manager(){
        this.db = null;
        this.getAll = function(){
            var all = [];
            this.db.all(queryGetAll, function(err, rows){
                if (err){
                    throw err;
                }
                all.push.apply(all, rows);
            });
            return all;
        }
}

I know nodejs is asynch, so it means the return is called before the end of the query. But I don't find examples on how I should use sqlite.

The line "return all" in your example will be executed BEFORE this.db.all() calls your callback. In order for your code to work you need to do something like this:

var queryGetAll = 'SELECT id, title, description, modified, lat, lng, zoom FROM maps';
function Manager(){
        this.db = null;
        // Allow a callback function to be passed to getAll
        this.getAll = function(callback){
            this.db.all(queryGetAll, function(err, rows){
                if (err){
                    // call your callback with the error
                    callback(err);
                    return;
                }
                // call your callback with the data
                callback(null, rows);
                return;
            });
        }
}