github.com/yrj2011/jx-test-infra@v0.0.0-20190529031832-7a2065ee98eb/triage/node_modules/inflight/README.md (about)

     1  # inflight
     2  
     3  Add callbacks to requests in flight to avoid async duplication
     4  
     5  ## USAGE
     6  
     7  ```javascript
     8  var inflight = require('inflight')
     9  
    10  // some request that does some stuff
    11  function req(key, callback) {
    12    // key is any random string.  like a url or filename or whatever.
    13    //
    14    // will return either a falsey value, indicating that the
    15    // request for this key is already in flight, or a new callback
    16    // which when called will call all callbacks passed to inflightk
    17    // with the same key
    18    callback = inflight(key, callback)
    19  
    20    // If we got a falsey value back, then there's already a req going
    21    if (!callback) return
    22  
    23    // this is where you'd fetch the url or whatever
    24    // callback is also once()-ified, so it can safely be assigned
    25    // to multiple events etc.  First call wins.
    26    setTimeout(function() {
    27      callback(null, key)
    28    }, 100)
    29  }
    30  
    31  // only assigns a single setTimeout
    32  // when it dings, all cbs get called
    33  req('foo', cb1)
    34  req('foo', cb2)
    35  req('foo', cb3)
    36  req('foo', cb4)
    37  ```