Remove dependency on 'async'

This commit removes the last current dependency of Cylon, 'async'.

In it's place, simplified versions of the methods used have been added
so lib/utils/helpers.js.

lib/cylon.js

@@ -8,8 +8,6 @@
 
 "use strict";
 
-var Async = require("async");
-
 var Logger = require("./logger"),
     Robot = require("./robot"),
     Config = require("./config"),
@@ -113,7 +111,7 @@ Cylon.api = function api(Server, opts) {
 Cylon.start = function start() {
   var starters = _.pluck(this.robots, "start");
 
-  Async.parallel(starters, function() {
+  _.parallel(starters, function() {
     var mode = Utils.fetch(Config, "workMode", "async");
 
     if (mode === "sync") {
@@ -157,7 +155,7 @@ Cylon.halt = function halt(callback) {
   var timeout = Config.haltTimeout || 3000;
   Utils.after(timeout, callback);
 
-  Async.parallel(fns, callback);
+  _.parallel(fns, callback);
 };
 
 Cylon.toJSON = function() {

lib/robot.js

@@ -16,8 +16,7 @@ var initializer = require("./initializer"),
 
 var validator = require("./validator");
 
-var Async = require("async"),
+var EventEmitter = require("events").EventEmitter;
-    EventEmitter = require("events").EventEmitter;
 
 // used when creating default robot names
 var ROBOT_ID = 1;
@@ -288,7 +287,7 @@ Robot.prototype.start = function(callback) {
     }
   }.bind(this);
 
-  Async.series([
+  _.series([
     this.startConnections,
     this.startDevices,
     start
@@ -356,7 +355,7 @@ Robot.prototype.startConnections = function(callback) {
     }.bind(this);
   }, this);
 
-  return Async.parallel(starters, callback);
+  return _.parallel(starters, callback);
 };
 
 /**
@@ -386,7 +385,7 @@ Robot.prototype.startDevices = function(callback) {
     };
   }, this);
 
-  return Async.parallel(starters, callback);
+  return _.parallel(starters, callback);
 };
 
 /**
@@ -406,8 +405,8 @@ Robot.prototype.halt = function(callback) {
       connections = _.pluck(this.connections, "disconnect");
 
   try {
-    Async.parallel(devices, function() {
+    _.parallel(devices, function() {
-      Async.parallel(connections, callback);
+      _.parallel(connections, callback);
     });
   } catch (e) {
     var msg = "An error occured while attempting to safely halt the robot";

lib/utils/helpers.js

@@ -8,6 +8,8 @@
 
 "use strict";
 
+/* eslint no-use-before-define: 0 */
+
 var __slice = Array.prototype.slice;
 
 var H = module.exports = {};
@@ -210,3 +212,68 @@ function includes(arr, value) {
 extend(H, {
   includes: includes
 });
+
+function parallel(functions, done) {
+  var total = functions.length,
+      completed = 0,
+      results = [],
+      error;
+
+  function callback(err, result) {
+    if (error) {
+      return;
+    }
+
+    if (err || error) {
+      error = err;
+      done(err);
+      return;
+    }
+
+    completed++;
+    results.push(result);
+
+    if (completed === total) {
+      done(null, results);
+    }
+  }
+
+  if (!functions.length) { done(); }
+
+  functions.forEach(function(fn) { fn(callback); });
+}
+
+extend(H, {
+  parallel: parallel
+});
+
+function series(functions, done) {
+  var results = [],
+      error;
+
+  function callback(err, result) {
+    if (err || error) {
+      error = err;
+      return done(err);
+    }
+
+    results.push(result);
+
+    if (!functions.length) {
+      return done(null, results);
+    }
+
+    next();
+  }
+
+  function next() {
+    functions.shift()(callback);
+  }
+
+  if (!functions.length) { done(null, results); }
+  next();
+}
+
+extend(H, {
+  series: series
+});

package.json

@@ -37,7 +37,6 @@
   "hardware": {
     "*": false,
     "./": false,
-    "async": true,
     "./lib": true
   },
 
@@ -51,9 +50,5 @@
     "mocha":      "2.2.4",
     "sinon":      "1.14.1",
     "eslint":     "0.22.1"
-  },
-
-  "dependencies": {
-    "async": "0.9.0"
   }
 }

spec/lib/utils/helpers.spec.js

@@ -289,4 +289,90 @@ describe("Helpers", function() {
       expect(fn(arr, {})).to.be.eql(false);
     });
   });
+
+  describe("#parallel", function() {
+    var fn1, fn2, fn3, callback;
+
+    beforeEach(function() {
+      fn1 = stub();
+      fn2 = stub();
+      fn3 = stub();
+      callback = stub();
+    });
+
+    it("executes a set of functions in parallel", function() {
+      _.parallel([fn1, fn2, fn3], callback);
+
+      expect(fn1).to.be.called;
+      expect(fn2).to.be.called;
+      expect(fn3).to.be.called;
+      expect(callback).to.not.be.called;
+
+      fn1.yield(null, true);
+      expect(callback).to.not.be.called;
+      fn2.yield(null, true);
+      expect(callback).to.not.be.called;
+      fn3.yield(null, true);
+
+      expect(callback).to.be.calledWith(null, [true, true, true]);
+    });
+
+    it("stops immediately if there's an error", function() {
+      _.parallel([fn1, fn2, fn3], callback);
+
+      fn1.yield(true, null);
+
+      expect(callback).to.be.calledWith(true);
+
+      fn2.yields(null, true);
+      fn3.yields(null, true);
+
+      expect(callback).to.be.calledOnce;
+    });
+  });
+
+  describe("#series", function() {
+    var fn1, fn2, fn3, callback;
+
+    beforeEach(function() {
+      fn1 = stub();
+      fn2 = stub();
+      fn3 = stub();
+      callback = stub();
+    });
+
+    it("executes a set of functions in series", function() {
+      _.series([fn1, fn2, fn3], callback);
+
+      expect(fn1).to.be.called;
+      expect(fn2).to.not.be.called;
+      expect(fn3).to.not.be.called;
+      expect(callback).to.not.be.called;
+
+      fn1.yield(null, true);
+
+      expect(fn2).to.be.called;
+      expect(fn3).to.not.be.called;
+      expect(callback).to.not.be.called;
+
+      fn2.yield(null, true);
+
+      expect(fn3).to.be.called;
+      expect(callback).to.not.be.called;
+
+      fn3.yield(null, true);
+
+      expect(callback).to.be.calledWith(null, [true, true, true]);
+    });
+
+    it("stops immediately if there's an error", function() {
+      _.series([fn1, fn2, fn3], callback);
+
+      fn1.yield(true, null);
+
+      expect(fn2).to.not.be.called;
+      expect(fn3).to.not.be.called;
+      expect(callback).to.be.calledWith(true);
+    });
+  });
 });