inflight-stable

A maintained version of the inflight module.

Installation

npm install inflight-stable

Usage

var inflight = require('inflight-stable')

function fetchData(key, callback) {
  var makeRequest = inflight(key, callback)
  
  if (makeRequest) {
    // First call - make the actual request
    doAsyncOperation(function(err, data) {
      makeRequest(err, data)
    })
  }
  // Subsequent calls return null and queue the callback
}

What it does

Ensures multiple calls with the same key will queue up and all receive the same result, rather than executing the same operation multiple times.

API

inflight(key, callback)

Returns a callback function on first call, null on subsequent calls. Call the returned function to trigger all queued callbacks.

Migration

// Before
var inflight = require('inflight')

// After
var inflight = require('inflight-stable')

Why?

isaacs deprecated inflight because of an apparent memory leak, though it's only really a memory leak if the user never calls the callback, so there's no bug in the code. He suggests using lru-cache, but that module isn't as backwards-compatible. So this is a maintained version of inflight that isn't completely deprecated. This version has a few slight design changes from the original, but works the same.

License

MIT