async.each nested in async.waterfall

[maddy2308]

I have recently started using async api. Now my requirement is to perform a join on 3 collections namely fields, scripts and statements. fields can have multiple scripts, and scripts can have multiple statements.

here is what I have tried so far:(to join Fields collection with scripts)

// Array to hold async tasks
var asyncTasks = [];

async.waterfall([
function(callback){
// fetches fields based on some Id and it returns 2 fields
db.fields.find({entity_id: mongojs.ObjectId("54440a448bbbcbb4070131ab")}, function (err, fields) {
console.log(JSON.stringify(fields, null, 2));
callback(null, fields);
})
},
function(arg1, callback){
// arg1 now equals fields
arg1.forEach(function(eachField){
asyncTasks.push(function(callback){
db.scripts.find({fieldId: eachField._id.valueOf()}, function(err, scripts) {
// Async call is done then alert via callback
console.log(JSON.stringify(scripts, null, 2));
callback(null, scripts);
});
});
});

    // Now we have an array of functions doing async tasks
    // Execute all async tasks in the asyncTasks array
    async.parallel(asyncTasks, function(err, results) {
        // All tasks are done now
        console.log("Scripts" + JSON.stringify(results, null, 2));
        callback(null, "done");
    });

}

], function (err, result) {
console.log(result);
});
// for the above code here is what i get the output
[
{
"_id": "54440a548bbbcbb4070131ac",
"name": "t1",
"type": "String",
"entity_id": "54440a448bbbcbb4070131ab"
},
{
"_id": "54447f1d20c103981fa1a27c",
"name": "t2",
"type": "String",
"entity_id": "54440a448bbbcbb4070131ab"
}
]
size of array 2
[]
[]
Scripts[
[],
[]
]
done
The above output doesn't print any scripts even though there are 2 scripts in database. My database is is in MongoDB, and i am using NodeJs, MongoJS api. why is db.scripts.find() returning empty array?

I tested this piece of code to see if scripts returning the o/p. Please find below my code

test2();
function test2(){

    var getScriptFunction = function(eachField, doneCallback){
        if(eachField !== undefined) {
            var fieldId = eachField;
            console.log(fieldId);
            db.scripts.find({fieldId: fieldId}, function (err, result) {
                // Async call is done, alert via callback
                doneCallback(null, result);
            });
        }
    }
    // The array is the id of fields
    async.map(["54440a548bbbcbb4070131ac", "54447f1d20c103981fa1a27c"], getScriptFunction, function (err, results) {
        // Square has been called on each of the numbers
        // so we're now done!
        if (err){
            console.log("error!" + err);
        } else {
            console.log("printed from helper function \n" + JSON.stringify(results, null, 2));
        }
    });
}

This is the o/p of the above code to fetch scripts ran individually

printed from helper function
[
[
{
"_id": "54440a678bbbcbb4070131ad",
"name": "s1",
"fieldId": "54440a548bbbcbb4070131ac"
},
{
"_id": "544af260eb7a486824a5c306",
"name": "s2",
"fieldId": "54440a548bbbcbb4070131ac"
}
],
[]
]
This is how fields look like (db.fields.find().pretty())

[
{
"_id": "54440a548bbbcbb4070131ac",
"name": "t1",
"type": "String",
"entity_id": "54440a448bbbcbb4070131ab"
},
{
"_id": "54447f1d20c103981fa1a27c",
"name": "t2",
"type": "String",
"entity_id": "54440a448bbbcbb4070131ab"
}
]

[RyanCopley]

I believe I've done this and am willing to help if you properly format your post to make it legible. Please include code tags