Files: 038a737d7b268452a2d1ca1cd1e3ade9b5e966ff / 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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