javascript - When does the loading of data occur in Firebase? -

javascript - When does the loading of data occur in Firebase? -

my info sorted date , incremental id this:

20140622 value_1 value_2 20140623 value_3 value_4

in order observe when new date added, set on('child_added') listener, , on('child_added') listener observe new values within date because on('child_added') triggered immediate childs.

to avoid double bandwith usage , create load faster, i'd know in moment transfer of info of snapshot occurs: when define new kid or when utilize .val() function?

data downloaded when found listener using on() or once() , remains cached locally , synced until listeners disconnected.

it's not necessary found child_added listener nested children, since exist in info downloaded part of parent:

var ref = new firebase(url); ref.on('child_added', function(snap) { console.log('parent rec', snap.name()); snap.foreach(function(childsnap) { console.log('child rec', childsnap.name()); }); });

however, there no harm in nested child_added events; optimized internally firebase , values returned , locally cached data:

var ref = new firebase(url); ref.on('child_added', function(snap) { console.log('parent rec', snap.name()); snap.ref().on('child_added', function(snap) { console.log('child rec', snap.nam()); }); });

the caveat here if want phone call off() on event listeners later, must disconnected before server connection severed , cached info purged.

javascript firebase