initial commit

node_modules/slide/lib/async-map.js

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+
+/*
+usage:
+
+// do something to a list of things
+asyncMap(myListOfStuff, function (thing, cb) { doSomething(thing.foo, cb) }, cb)
+// do more than one thing to each item
+asyncMap(list, fooFn, barFn, cb)
+
+*/
+
+module.exports = asyncMap
+
+function asyncMap () {
+  var steps = Array.prototype.slice.call(arguments)
+    , list = steps.shift() || []
+    , cb_ = steps.pop()
+  if (typeof cb_ !== "function") throw new Error(
+    "No callback provided to asyncMap")
+  if (!list) return cb_(null, [])
+  if (!Array.isArray(list)) list = [list]
+  var n = steps.length
+    , data = [] // 2d array
+    , errState = null
+    , l = list.length
+    , a = l * n
+  if (!a) return cb_(null, [])
+  function cb (er) {
+    if (er && !errState) errState = er
+
+    var argLen = arguments.length
+    for (var i = 1; i < argLen; i ++) if (arguments[i] !== undefined) {
+      data[i - 1] = (data[i - 1] || []).concat(arguments[i])
+    }
+    // see if any new things have been added.
+    if (list.length > l) {
+      var newList = list.slice(l)
+      a += (list.length - l) * n
+      l = list.length
+      process.nextTick(function () {
+        newList.forEach(function (ar) {
+          steps.forEach(function (fn) { fn(ar, cb) })
+        })
+      })
+    }
+
+    if (--a === 0) cb_.apply(null, [errState].concat(data))
+  }
+  // expect the supplied cb function to be called
+  // "n" times for each thing in the array.
+  list.forEach(function (ar) {
+    steps.forEach(function (fn) { fn(ar, cb) })
+  })
+}