Files: 43df95c4d63b7a5a52000171ed8ae86b874f3b5a / util.js
1099 bytesRaw
1 | var pull = require('pull-stream') |
2 | var Next = require('pull-next') |
3 | |
4 | function get (obj, path) { |
5 | if(!obj) return undefined |
6 | if('string' === typeof path) return obj[path] |
7 | if(Array.isArray(path)) { |
8 | for(var i = 0; obj && i < path.length; i++) |
9 | obj = obj[path[i]] |
10 | return obj |
11 | } |
12 | } |
13 | |
14 | function clone (obj) { |
15 | var _obj = {} |
16 | for(var k in obj) _obj[k] = obj[k] |
17 | return _obj |
18 | } |
19 | |
20 | exports.next = function (createStream, opts, property, range) { |
21 | |
22 | range = range || (opts.reverse ? 'lt' : 'gt') |
23 | property = property || 'timestamp' |
24 | |
25 | var last = null, count = -1 |
26 | return Next(function () { |
27 | if(last) { |
28 | if(count === 0) return |
29 | var value = opts[range] = get(last, property) |
30 | if(value == null) return |
31 | last = null |
32 | } |
33 | return pull( |
34 | createStream(clone(opts)), |
35 | pull.through(function (msg) { |
36 | count ++ |
37 | if(!msg.sync) { |
38 | last = msg |
39 | } |
40 | }, function (err) { |
41 | //retry on errors... |
42 | if(err) return count = -1 |
43 | //end stream if there were no results |
44 | if(last == null) last = {} |
45 | }) |
46 | ) |
47 | }) |
48 | } |
49 | |
50 | |
51 | |
52 |
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