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alanz / patchwork



forked from Matt McKegg / patchwork

Tree: e79d34134f281a91928cfc9729fcc40cdc3a88d4

Files: e79d34134f281a91928cfc9729fcc40cdc3a88d4 / lib / next-stepper.js

1190 bytesRaw
1const pull = require('pull-stream')
2const Next = require('pull-next')
3var ENDED = {}
4
5module.exports = nextStepper
6
7// TODO - this should be another module?
8
9function nextStepper (createStream, opts, range) {
10 range = range || (opts.reverse ? 'lt' : 'gt')
11
12 var last = null
13 var count = -1
14
15 return Next(function () {
16 if (last) {
17 if (count === 0) return
18 var value = opts[range] = last
19 if (value === ENDED) return
20 last = null
21 }
22 return pull(
23 createStream(clone(opts)),
24 pull.through(function (msg) {
25 count++
26 if (!msg.sync) {
27 last = msg
28 }
29 }, function (err) {
30 // retry on errors...
31 if (err) {
32 count = -1
33 return count
34 }
35 // end stream if there were no results
36 if (last == null) last = ENDED
37 })
38 )
39 })
40}
41
42function get (obj, path) {
43 if (!obj) return undefined
44 if (typeof path === 'string') return obj[path]
45 if (Array.isArray(path)) {
46 for (var i = 0; obj && i < path.length; i++) {
47 obj = obj[path[i]]
48 }
49 return obj
50 }
51}
52
53function clone (obj) {
54 var _obj = {}
55 for (var k in obj) _obj[k] = obj[k]
56 return _obj
57}
58

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