l0bsterssg

node.js static responsive blog post generator
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inflight.js (1365B)

      1 var wrappy = require('wrappy')
      2 var reqs = Object.create(null)
      3 var once = require('once')
      4 
      5 module.exports = wrappy(inflight)
      6 
      7 function 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 
     17 function 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 
     48 function 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 }