source: trip-planner-front/node_modules/inflight/inflight.js@ 571e0df

Last change on this file since 571e0df was 6a3a178, checked in by Ema <ema_spirova@…>, 3 years ago

initial commit

  • Property mode set to 100644
File size: 1.3 KB
Line 
1var wrappy = require('wrappy')
2var reqs = Object.create(null)
3var once = require('once')
4
5module.exports = wrappy(inflight)
6
7function inflight (key, cb) {
8 if (reqs[key]) {
9 reqs[key].push(cb)
10 return null
11 } else {
12 reqs[key] = [cb]
13 return makeres(key)
14 }
15}
16
17function makeres (key) {
18 return once(function RES () {
19 var cbs = reqs[key]
20 var len = cbs.length
21 var args = slice(arguments)
22
23 // XXX It's somewhat ambiguous whether a new callback added in this
24 // pass should be queued for later execution if something in the
25 // list of callbacks throws, or if it should just be discarded.
26 // However, it's such an edge case that it hardly matters, and either
27 // choice is likely as surprising as the other.
28 // As it happens, we do go ahead and schedule it for later execution.
29 try {
30 for (var i = 0; i < len; i++) {
31 cbs[i].apply(null, args)
32 }
33 } finally {
34 if (cbs.length > len) {
35 // added more in the interim.
36 // de-zalgo, just in case, but don't call again.
37 cbs.splice(0, len)
38 process.nextTick(function () {
39 RES.apply(null, args)
40 })
41 } else {
42 delete reqs[key]
43 }
44 }
45 })
46}
47
48function slice (args) {
49 var length = args.length
50 var array = []
51
52 for (var i = 0; i < length; i++) array[i] = args[i]
53 return array
54}
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