javascript - How can I know when a Firebase query has ended -


i want collect recent 10 items datastore. believe supposed using .child() , .limittolast(), emits event every time result has been added child.

i don't know if there 10 items in total, simple counter won't work.

how know when firebase finished giving me results?

example lookup code:

var plots = []; firebasedatastore.child("plots").orderbychild("unicode-timestamp").limittolast(10).on("child_added", function(snapshot) {     // add new item list     plots.push(snapshot.val()); });

i need know when final plot has been added, regardless of whether has hit limit.

a firebase query never ends. continues monitor (in case) plots unicode-timestamp , keep "window" of last 10 plots.

so:

  • child_added:timestamp1
  • child_added:timestamp2
  • ...
  • child_added:timestamp9
  • child_added:timestamp10

and when add plot:

  • child_removed:timestamp1
  • child_added:timestamp11

if not looking use behavior, have 2 options:

  1. use value event , snapshot.foreach on child nodes
  2. keep counter , off listener when you've reached number of children expect

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