coffeescript looping through array and adding values - arrays

Question

What I'd like to do is add an array of students to each manager (in an array).
This is where I'm getting stuck:
for sup in sups
do(sup) ->
sup.students_a = "This one works"
getStudents sup.CLKEY, (studs) ->
sup.students_b = "This one doesn't"
cback sups
EDIT: After some thought, what may be happening is that it is adding the "sudents_b" data to the sups array, but the sups array is being returned (via cback function) before this work is performed. Thus, I suppose I should move that work to a function and only return sups after another callback is performed?
For context, here's the gist of this code:
odbc = require "odbc"
module.exports.run = (managerId, cback) ->
db2 = new odbc.Database()
conn = "dsn=mydsn;uid=myuid;pwd=mypwd;database=mydb"
db2.open conn, (err) ->
throw err if err
sortBy = (key, a, b, r) ->
r = if r then 1 else -1
return -1*r if a[key] > b[key]
return +1*r if b[key] > a[key]
return 0
getDB2Rows = (sql, params, cb) ->
db2.query sql, params, (err, rows, def) ->
if err? then console.log err else cb rows
getManagers = (mid, callback) ->
supers = []
queue = []
querySupers = (id, cb) ->
sql = "select distinct mycolumns where users.id = ? and users.issupervisor = 1"
getDB2Rows sql, [id], (rows) ->
for row in rows
do(row) ->
if supers.indexOf row is -1 then supers.push row
if queue.indexOf row is -1 then queue.push row
cb null
addSupers = (id) -> # todo: add limit to protect against infinate loop
querySupers id, (done) ->
shiftrow = queue.shift()
if shiftrow? and shiftrow['CLKEY']? then addSupers shiftrow['CLKEY'] else
callback supers
addMain = (id) ->
sql = "select mycolumns where users.id = ? and users.issupervisor = 1"
getDB2Rows sql, [id], (rows) ->
supers.push row for row in rows
addMain mid
addSupers mid
getStudents = (sid, callb) ->
students = []
sql = "select mycols from mytables where myconditions and users.supervisor = ?"
getDB2Rows sql, [sid], (datas) ->
students.push data for data in datas
callb students
console.log "Compiling Array of all Managers tied to ID #{managerId}..."
getManagers managerId, (sups) ->
console.log "Built array of #{sups.length} managers"
sups.sort (a,b) ->
sortBy('MLNAME', a, b) or # manager's manager
sortBy('LNAME', a, b) # manager
for sup in sups
do(sup) ->
sup.students_a = "This one works"
getStudents sup.CLKEY, (studs) ->
sup.students_b = "This one doesn't"
cback sups

Answer 1

You are correct that your callback cback subs is executed before even the first getStudents has executed it's callback with the studs array. Since you want to do this for a whole array, it can grow a little hairy with just a for loop.
I always recommend async for these things:
getter = (sup, callback) ->
getStudents sup.CLKEY, callback
async.map sups, getter, (err, results) ->
// results is an array of results for each sup
callback() // <-- this is where you do your final callback.
Edit: Or if you want to put students on each sup, you would have this getter:
getter = (sup, callback) ->
getStudents sup.CLKEY, (studs) ->
sup.students = studs
// async expects err as the first parameter to callbacks, as is customary in node
callback null, sup
Edit: Also, you should probably follow the node custom of passing err as the first argument to all callbacks, and do proper error checking.