From 6e3d7c66677f84b384d03c1803ac74fe74c4865d Mon Sep 17 00:00:00 2001
From: Andrew Stewart <andrew@stwrt.ca>
Date: Fri, 20 Feb 2015 18:49:31 -0800
Subject: [PATCH] Add helpers to replace some lodash functionality

Not a 1:1, and probably much slower than Lodash's ultra-optimised
implementations, but we do enough I/O that it's not really relevant,
is it?
---
 lib/adaptor.js                 |  12 +-
 lib/basestar.js                |   5 +-
 lib/cylon.js                   |  50 ++------
 lib/driver.js                  |  10 +-
 lib/initializer.js             |  23 ++--
 lib/logger.js                  |   6 +-
 lib/robot.js                   | 113 +++++------------
 lib/utils.js                   |  59 ++-------
 lib/utils/helpers.js           | 156 +++++++++++++++++++++++
 spec/lib/utils.spec.js         |  33 -----
 spec/lib/utils/helpers.spec.js | 223 +++++++++++++++++++++++++++++++++
 11 files changed, 457 insertions(+), 233 deletions(-)
 create mode 100644 lib/utils/helpers.js
 create mode 100644 spec/lib/utils/helpers.spec.js

diff --git a/lib/adaptor.js b/lib/adaptor.js
index 91e536e..6a2b7ff 100644
--- a/lib/adaptor.js
+++ b/lib/adaptor.js
@@ -9,7 +9,8 @@
 "use strict";
 
 var Basestar = require("./basestar"),
-    Utils = require("./utils");
+    Utils = require("./utils"),
+    _ = require("./utils/helpers");
 
 // Public: Creates a new Adaptor
 //
@@ -33,14 +34,11 @@ var Adaptor = module.exports = function Adaptor(opts) {
   // misc. details provided in args hash
   this.details = {};
 
-  for (var name in opts) {
-    var opt = opts[name],
-        banned = ["robot", "name", "adaptor", "events"];
-
-    if (!~banned.indexOf(name)) {
+  _.each(opts, function(opt, name) {
+    if (!~["robot", "name", "adaptor", "events"].indexOf(name)) {
       this.details[name] = opt;
     }
-  }
+  }, this);
 };
 
 Utils.subclass(Adaptor, Basestar);
diff --git a/lib/basestar.js b/lib/basestar.js
index 92912e9..7e05292 100644
--- a/lib/basestar.js
+++ b/lib/basestar.js
@@ -10,7 +10,8 @@
 
 var EventEmitter = require("events").EventEmitter;
 
-var Utils = require("./utils");
+var Utils = require("./utils"),
+    _ = require("./utils/helpers");
 
 // Basestar is a base class to be used when writing external Cylon adaptors and
 // drivers. It provides some useful base methods and functionality
@@ -83,7 +84,7 @@ Basestar.prototype.defineDriverEvent = function(opts) {
 };
 
 Basestar.prototype._proxyEvents = function(opts, source, target) {
-  opts = (typeof opts === "string") ? { eventName: opts } : opts;
+  opts = _.isString(opts) ? { eventName: opts } : opts;
 
   opts.source = source;
   opts.target = target;
diff --git a/lib/cylon.js b/lib/cylon.js
index b7f78c3..21e311c 100644
--- a/lib/cylon.js
+++ b/lib/cylon.js
@@ -13,7 +13,8 @@ var Async = require("async");
 var Logger = require("./logger"),
     Robot = require("./robot"),
     Config = require("./config"),
-    Utils = require("./utils");
+    Utils = require("./utils"),
+    _ = require("./utils/helpers");
 
 var EventEmitter = require("events").EventEmitter;
 
@@ -73,19 +74,15 @@ Cylon.robot = function robot(opts) {
 //
 // Returns nothing
 Cylon.api = function api(Server, opts) {
-  var isObject   = function(arg) { return typeof arg === "object"; },
-      isFunction = function(arg) { return typeof arg === "function"; },
-      isString   = function(arg) { return typeof arg === "string"; };
-
   // if only passed options (or nothing), assume HTTP server
-  if (Server == null || isObject(Server) && !isFunction(Server)) {
+  if (Server == null || _.isObject(Server) && !_.isFunction(Server)) {
     opts = Server;
     Server = "http";
   }
 
   opts = opts || {};
 
-  if (isString(Server)) {
+  if (_.isString(Server)) {
     var req = "cylon-api-" + Server;
 
     try {
@@ -106,9 +103,7 @@ Cylon.api = function api(Server, opts) {
           ];
         }
 
-        messages.forEach(function(str) {
-          Logger.error(str);
-        });
+        _.each(messages, _.arity(Logger.error, 1));
         return;
       } else {
         throw e;
@@ -126,22 +121,13 @@ Cylon.api = function api(Server, opts) {
 //
 // Returns nothing
 Cylon.start = function start() {
-  var starters = [],
-      name;
-
-  for (name in this.robots) {
-    var bot = this.robots[name];
-    starters.push(bot.start.bind(bot));
-  }
+  var starters = _.pluck(this.robots, "start");
 
   Async.parallel(starters, function() {
     var mode = Utils.fetch(Config, "workMode", "async");
 
     if (mode === "sync") {
-      for (name in this.robots) {
-        var bot = this.robots[name];
-        bot.startWork.call(bot);
-      }
+      _.invoke(this.robots, "startWork");
     }
   }.bind(this));
 };
@@ -153,11 +139,11 @@ Cylon.start = function start() {
 // Returns the current config
 Cylon.config = function(opts) {
   var loggingChanged = (
-    opts.logging && Config.logging !== Utils.merge(Config.logging, opts.logging)
+    opts.logging && Config.logging !== _.extend(Config.logging, opts.logging)
   );
 
-  if (typeof opts === "object" && !Array.isArray(opts)) {
-    Config = Utils.merge(Config, opts);
+  if (_.isObject(opts)) {
+    Config = _.extend(Config, opts);
   }
 
   if (loggingChanged) {
@@ -175,12 +161,7 @@ Cylon.config = function(opts) {
 Cylon.halt = function halt(callback) {
   callback = callback || function() {};
 
-  var fns = [];
-
-  for (var name in this.robots) {
-    var bot = this.robots[name];
-    fns.push(bot.halt.bind(bot));
-  }
+  var fns = _.pluck(this.robots, "halt");
 
   // if robots can"t shut down quickly enough, forcefully self-terminate
   var timeout = Config.haltTimeout || 3000;
@@ -190,15 +171,8 @@ Cylon.halt = function halt(callback) {
 };
 
 Cylon.toJSON = function() {
-  var robots = [];
-
-  for (var name in this.robots) {
-    var bot = this.robots[name];
-    robots.push(bot.toJSON.call(bot));
-  }
-
   return {
-    robots: robots,
+    robots: _.invoke(this.robots, "toJSON"),
     commands: Object.keys(this.commands),
     events: this.events
   };
diff --git a/lib/driver.js b/lib/driver.js
index 21725ec..abd8328 100644
--- a/lib/driver.js
+++ b/lib/driver.js
@@ -9,7 +9,8 @@
 "use strict";
 
 var Basestar = require("./basestar"),
-    Utils = require("./utils");
+    Utils = require("./utils"),
+    _ = require("./utils/helpers");
 
 // Public: Creates a new Driver
 //
@@ -35,14 +36,13 @@ var Driver = module.exports = function Driver(opts) {
 
   this.details = {};
 
-  for (var name in opts) {
-    var opt = opts[name],
-        banned = ["robot", "name", "connection", "driver", "events"];
+  _.each(opts, function(opt, name) {
+    var banned = ["robot", "name", "connection", "driver", "events"];
 
     if (!~banned.indexOf(name)) {
       this.details[name] = opt;
     }
-  }
+  }, this);
 };
 
 Utils.subclass(Driver, Basestar);
diff --git a/lib/initializer.js b/lib/initializer.js
index 0f75ce9..eb414c1 100644
--- a/lib/initializer.js
+++ b/lib/initializer.js
@@ -9,14 +9,15 @@
 "use strict";
 
 var Registry = require("./registry"),
-    Config = require("./config");
+    Config = require("./config"),
+    _ = require("./utils/helpers");
 
 function testMode() {
   return process.env.NODE_ENV === "test" && Config.testMode;
 }
 
 module.exports = function Initializer(type, opts) {
-  var mod, name, prop;
+  var mod;
 
   mod = Registry.findBy(type, opts[type]);
 
@@ -32,28 +33,24 @@ module.exports = function Initializer(type, opts) {
 
   var obj = mod[type](opts);
 
-  for (name in obj) {
-    prop = obj[name];
-
+  _.each(obj, function(prop, name) {
     if (name === "constructor") {
-      continue;
+      return;
     }
 
-    if (typeof prop === "function") {
+    if (_.isFunction(prop)) {
       obj[name] = prop.bind(obj);
     }
-  }
+  });
 
   if (testMode()) {
     var test = Registry.findBy(type, "test")[type](opts);
 
-    for (name in obj) {
-      prop = obj[name];
-
-      if (typeof prop === "function" && !test[name]) {
+    _.each(obj, function(prop, name) {
+      if (_.isFunction(prop) && !test[name]) {
         test[name] = function() { return true; };
       }
-    }
+    });
 
     return test;
   }
diff --git a/lib/logger.js b/lib/logger.js
index 5c1dc50..e79b6b2 100644
--- a/lib/logger.js
+++ b/lib/logger.js
@@ -13,12 +13,12 @@ var levels = ["debug", "info", "warn", "error", "fatal"];
 var BasicLogger = require("./logger/basic_logger"),
     NullLogger = require("./logger/null_logger"),
     Config = require("./config"),
-    Utils = require("./utils");
+    _ = require("./utils/helpers");
 
 var Logger = module.exports = {
   setup: function(opts) {
-    if (typeof opts === "object") {
-      Config.logging = Utils.merge(Config.logging, opts);
+    if (_.isObject(opts)) {
+      Config.logging = _.extend(Config.logging, opts);
     }
 
     var logger = Config.logging.logger,
diff --git a/lib/robot.js b/lib/robot.js
index 7a8213d..2796e67 100644
--- a/lib/robot.js
+++ b/lib/robot.js
@@ -11,7 +11,8 @@
 var initializer = require("./initializer"),
     Logger = require("./logger"),
     Utils = require("./utils"),
-    Config = require("./config");
+    Config = require("./config"),
+    _ = require("./utils/helpers");
 
 var Async = require("async"),
     EventEmitter = require("events").EventEmitter;
@@ -48,30 +49,28 @@ var Robot = module.exports = function Robot(opts) {
   this.initConnections(opts);
   this.initDevices(opts);
 
-  for (var name in opts) {
-    var opt = opts[name];
-
+  _.each(opts, function(opt, name) {
     if (this[name] !== undefined) {
-      continue;
+      return;
     }
 
     this[name] = opt;
 
-    if (opts.commands == null && typeof opt === "function") {
+    if (opts.commands == null && _.isFunction(opt)) {
       this.commands[name] = opt;
     }
-  }
+  }, this);
 
   if (opts.commands) {
     var cmds;
 
-    if (typeof opts.commands === "function") {
+    if (_.isFunction(opts.commands)) {
       cmds = opts.commands.call(this);
     } else {
       cmds = opts.commands;
     }
 
-    if (typeof cmds === "object" && !Array.isArray(cmds)) {
+    if (_.isObject(cmds)) {
       this.commands = cmds;
     } else {
       var err = "#commands must be an object ";
@@ -101,26 +100,12 @@ Robot.randomName = function() {
 //
 // Returns an Object containing Robot data
 Robot.prototype.toJSON = function() {
-  var connections = [],
-      devices = [],
-      n;
-
-  for (n in this.connections) {
-    var conn = this.connections[n];
-    connections.push(conn.toJSON.call(conn));
-  }
-
-  for (n in this.devices) {
-    var device = this.devices[n];
-    devices.push(device.toJSON.call(device));
-  }
-
   return {
     name: this.name,
-    connections: connections,
-    devices: devices,
+    connections: _.invoke(this.connections, "toJSON"),
+    devices: _.invoke(this.devices, "toJSON"),
     commands: Object.keys(this.commands),
-    events: Array.isArray(this.events) ? this.events : []
+    events: _.isArray(this.events) ? this.events : []
   };
 };
 
@@ -182,30 +167,28 @@ Robot.prototype.initConnections = function(opts) {
     return this.connections;
   }
 
-  if (typeof opts.connections === "object") {
-    if (Array.isArray(opts.connections)) {
+  if (_.isObjectLoose(opts.connections)) {
+    if (_.isArray(opts.connections)) {
       this.performArraySetup(opts.connections, "connection", "connections");
       return this.connections;
     }
 
-    for (var key in opts.connections) {
-      var conn = opts.connections[key],
-          name = typeof key === "string" ? key : conn.name;
+    _.each(opts.connections, function(conn, key) {
+      var name = _.isString(key) ? key : conn.name;
 
       if (conn.devices) {
         opts.devices = opts.devices || {};
 
-        for (var d in conn.devices) {
-          var device = conn.devices[d];
+        _.each(conn.devices, function(device, d) {
           device.connection = name;
           opts.devices[d] = device;
-        }
+        });
 
         delete conn.devices;
       }
 
       this.connection(name, conn);
-    }
+    }, this);
   }
 
   return this.connections;
@@ -226,7 +209,7 @@ Robot.prototype.device = function(name, device) {
     this.log("warn", str);
   }
 
-  if (typeof device.connection === "string") {
+  if (_.isString(device.connection)) {
     if (this.connections[device.connection] == null) {
       str = "No connection found with the name " + device.connection + ".\n";
       this.log("fatal", str);
@@ -269,18 +252,16 @@ Robot.prototype.initDevices = function(opts) {
     return this.devices;
   }
 
-  if (typeof opts.devices === "object") {
-    if (Array.isArray(opts.devices)) {
+  if (_.isObjectLoose(opts.devices)) {
+    if (_.isArray(opts.devices)) {
       this.performArraySetup(opts.devices, "device", "devices");
       return this.devices;
     }
 
-    for (var key in opts.devices) {
-      var device = opts.devices[key],
-          name = typeof key === "string" ? key : device.name;
-
+    _.each(opts.devices, function(device, key) {
+      var name = _.isString(key) ? key : device.name;
       this.device(name, device);
-    }
+    }, this);
   }
 
   return this.devices;
@@ -314,7 +295,7 @@ Robot.prototype.start = function(callback) {
       this.log("fatal", err);
 
       this.halt(function() {
-        if (typeof(this.error) === "function") {
+        if (_.isFunction(this.error)) {
           this.error.call(this, err);
         }
 
@@ -324,7 +305,7 @@ Robot.prototype.start = function(callback) {
       }.bind(this));
     }
 
-    if (typeof callback === "function") {
+    if (_.isFunction(callback)) {
       callback(err, results);
     }
   }.bind(this));
@@ -353,11 +334,7 @@ Robot.prototype.startWork = function() {
 Robot.prototype.startConnections = function(callback) {
   this.log("info", "Starting connections.");
 
-  var starters = [];
-
-  var createStarter = function(name) {
-    var conn = this.connections[name];
-
+  var starters = _.map(this.connections, function(conn, name) {
     this[name] = conn;
 
     return function(cb) {
@@ -372,11 +349,7 @@ Robot.prototype.startConnections = function(callback) {
       this.log("debug", str + ".");
       return conn.connect.call(conn, cb);
     }.bind(this);
-  }.bind(this);
-
-  for (var name in this.connections) {
-    starters.push(createStarter(name));
-  }
+  }, this);
 
   return Async.parallel(starters, callback);
 };
@@ -391,11 +364,7 @@ Robot.prototype.startDevices = function(callback) {
 
   log("info", "Starting devices.");
 
-  var starters = [];
-
-  var createStarter = function(name) {
-    var device = this.devices[name];
-
+  var starters = _.map(this.devices, function(device, name) {
     this[name] = device;
 
     return function(cb) {
@@ -408,12 +377,7 @@ Robot.prototype.startDevices = function(callback) {
       log("debug", str + ".");
       return device.start.call(device, cb);
     };
-
-  }.bind(this);
-
-  for (var name in this.devices) {
-    starters.push(createStarter(name));
-  }
+  }, this);
 
   return Async.parallel(starters, callback);
 };
@@ -432,19 +396,8 @@ Robot.prototype.halt = function(callback) {
     return callback();
   }
 
-  var devices = [],
-      connections = [],
-      n;
-
-  for (n in this.devices) {
-    var device = this.devices[n];
-    devices.push(device.halt.bind(device));
-  }
-
-  for (n in this.connections) {
-    var conn = this.connections[n];
-    connections.push(conn.disconnect.bind(conn));
-  }
+  var devices = _.pluck(this.devices, "halt"),
+      connections = _.pluck(this.connections, "disconnect");
 
   try {
     Async.parallel(devices, function() {
@@ -481,7 +434,7 @@ Robot.prototype.performArraySetup = function(things, typeOfThing, arrayName) {
   this.log("warn", str);
 
   things.forEach(function(t, key) {
-    var name = typeof key === "string" ? key : t.name;
+    var name = _.isString(key) === "string" ? key : t.name;
     this[typeOfThing](name, t);
   }, this);
 };
diff --git a/lib/utils.js b/lib/utils.js
index 577f8d9..fc0a411 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -8,6 +8,8 @@
 
 "use strict";
 
+var _ = require("./utils/helpers");
+
 var monkeyPatches = require("./utils/monkey-patches");
 
 var Utils = module.exports = {
@@ -106,13 +108,11 @@ var Utils = module.exports = {
   },
 
   proxyFunctions: function proxyFunctions(source, target) {
-    for (var key in source) {
-      var prop = source[key];
-
-      if (typeof prop === "function" && !target[key]) {
+    _.each(source, function(prop, key) {
+      if (_.isFunction(prop) && !target[key]) {
         target[key] = prop.bind(source);
       }
-    }
+    });
   },
 
   // Public: Proxies a list of methods from one object to another. It will not
@@ -133,7 +133,7 @@ var Utils = module.exports = {
     force = force || false;
 
     methods.forEach(function(method) {
-      if (typeof base[method] === "function" && !force) {
+      if (_.isFunction(base[method]) && !force) {
         return;
       }
 
@@ -187,7 +187,7 @@ var Utils = module.exports = {
       throw new Error("key not found: \"" + property + "\"");
     }
 
-    if (typeof(fallback) === "function") {
+    if (_.isFunction(fallback)) {
       var value = fallback(property);
 
       if (value === void 0) {
@@ -200,51 +200,6 @@ var Utils = module.exports = {
     return fallback;
   },
 
-  // Public: Merges two arrays/objects together, recursively.
-  //
-  // base   - what should be merged onto
-  // source - what should be merged into it
-  //
-  // Returns a merged object/array
-  merge: function(base, source) {
-    var isArray = Array.isArray(source);
-
-    if (base == null) {
-      base = isArray ? [] : {};
-    }
-
-    // merge objects
-    if (isArray) {
-      source.forEach(function(e, i) {
-        if (typeof base[i] === "undefined") {
-          base[i] = e;
-        } else if (typeof e === "object") {
-          base[i] = Utils.merge(base[i], e);
-        } else {
-          if (!~base.indexOf(e)) {
-            base.push(e);
-          }
-        }
-      });
-    } else {
-      var key;
-
-      for (key in source) {
-        if (typeof source[key] !== "object" || !source[key]) {
-          base[key] = source[key];
-        } else {
-          if (base[key]) {
-            Utils.merge(base[key], source[key]);
-          } else {
-            base[key] = source[key];
-          }
-        }
-      }
-    }
-
-    return base;
-  },
-
   // Public: Given a name, and an array of existing names, returns a unique
   // name.
   //
diff --git a/lib/utils/helpers.js b/lib/utils/helpers.js
new file mode 100644
index 0000000..9c93b37
--- /dev/null
+++ b/lib/utils/helpers.js
@@ -0,0 +1,156 @@
+// A collection of useful helper functions, used internally but not exported
+// with the rest of Cylon.
+
+"use strict";
+
+var __slice = Array.prototype.slice;
+
+var H = module.exports = {};
+
+function identity(value) {
+  return value;
+}
+
+function extend(base, source) {
+  var isArray = Array.isArray(source);
+
+  if (base == null) {
+    base = isArray ? [] : {};
+  }
+
+  if (isArray) {
+    source.forEach(function(e, i) {
+      if (typeof base[i] === "undefined") {
+        base[i] = e;
+      } else if (typeof e === "object") {
+        base[i] = extend(base[i], e);
+      } else {
+        if (!~base.indexOf(e)) {
+          base.push(e);
+        }
+      }
+    });
+  } else {
+    var key;
+
+    for (key in source) {
+      if (typeof source[key] !== "object" || !source[key]) {
+        base[key] = source[key];
+      } else {
+        if (base[key]) {
+          extend(base[key], source[key]);
+        } else {
+          base[key] = source[key];
+        }
+      }
+    }
+  }
+
+  return base;
+}
+
+extend(H, {
+  identity: identity,
+  extend: extend
+});
+
+function kind(thing) {
+  return Object.prototype.toString.call(thing).slice(8, -1);
+}
+
+function isA(type) {
+  return function(thing) {
+    return kind(thing) === type;
+  };
+}
+
+extend(H, {
+  isObject:      isA("Object"),
+  isObjectLoose: function(thing) { return typeof thing === "object"; },
+  isFunction:    isA("Function"),
+  isArray:       isA("Array"),
+  isString:      isA("String"),
+  isNumber:      isA("Number"),
+  isArguments:   isA("Arguments"),
+  isUndefined:   isA("Undefined")
+});
+
+function iterate(thing, fn, thisVal) {
+  if (H.isArray(thing)) {
+    thing.forEach(fn, thisVal);
+    return;
+  }
+
+  if (H.isObject(thing)) {
+    Object.keys(thing).forEach(function(key) {
+      var value = thing[key];
+      fn.call(thisVal, value, key);
+    }, thisVal);
+  }
+
+  return [];
+}
+
+function pluck(collection, key) {
+  var keys = [];
+
+  iterate(collection, function(object) {
+    if (H.isObject(object)) {
+      if (H.isFunction(object[key])) {
+        keys.push(object[key].bind(object));
+      } else {
+        keys.push(object[key]);
+      }
+    }
+  });
+
+  return keys;
+}
+
+function map(collection, fn, thisVal) {
+  var vals = [];
+
+  if (fn == null) {
+    fn = identity;
+  }
+
+  iterate(collection, function(object, index) {
+    vals.push(fn.call(thisVal, object, index));
+  });
+
+  return vals;
+}
+
+function invoke(collection, fn) {
+  var args = __slice.call(arguments, 2),
+      vals = [];
+
+  iterate(collection, function(object) {
+    if (H.isFunction(fn)) {
+      vals.push(fn.apply(object, args));
+      return;
+    }
+
+    vals.push(object[fn].apply(object, arguments));
+  });
+
+  return vals;
+}
+
+extend(H, {
+  pluck: pluck,
+  each: iterate,
+  map: map,
+  invoke: invoke
+});
+
+function arity(fn, n) {
+  return function() {
+    var args = __slice.call(arguments, 0, n);
+    return fn.apply(null, args);
+  };
+}
+
+extend(H, {
+  arity: arity
+});
diff --git a/spec/lib/utils.spec.js b/spec/lib/utils.spec.js
index 530f5a2..4977907 100644
--- a/spec/lib/utils.spec.js
+++ b/spec/lib/utils.spec.js
@@ -252,37 +252,4 @@ describe("Utils", function() {
       });
     });
   });
-
-  describe("#merge", function() {
-    var merge = utils.merge;
-
-    var base = {
-      fruits: ["apple"],
-      vegetables: ["beet"],
-      thing: null,
-      otherThing: "hello!",
-      data: [{ "user": "barney" }, { "user": "fred" }]
-    };
-
-    var source = {
-      fruits: ["banana"],
-      vegetables: ["carrot"],
-      thing: "hello!",
-      otherThing: null,
-      data: [{ "age": 36 }, { "age": 40 }]
-    };
-
-    var expected = {
-      data: [ { age: 36, user: "barney" }, { age: 40, user: "fred" } ],
-      fruits: [ "apple", "banana" ],
-      vegetables: [ "beet", "carrot" ],
-      thing: "hello!",
-      otherThing: null
-    };
-
-    it("merges two objects", function() {
-      var merged = merge(base, source);
-      expect(merged).to.be.eql(expected);
-    });
-  });
 });
diff --git a/spec/lib/utils/helpers.spec.js b/spec/lib/utils/helpers.spec.js
new file mode 100644
index 0000000..45843ab
--- /dev/null
+++ b/spec/lib/utils/helpers.spec.js
@@ -0,0 +1,223 @@
+"use strict";
+
+var _ = source("utils/helpers");
+
+describe("Helpers", function() {
+  describe("extend", function() {
+    var extend = _.extend;
+
+    var base = {
+      fruits: ["apple"],
+      vegetables: ["beet"],
+      thing: null,
+      otherThing: "hello!",
+      data: [{ "user": "barney" }, { "user": "fred" }]
+    };
+
+    var source = {
+      fruits: ["banana"],
+      vegetables: ["carrot"],
+      thing: "hello!",
+      otherThing: null,
+      data: [{ "age": 36 }, { "age": 40 }]
+    };
+
+    var expected = {
+      data: [ { age: 36, user: "barney" }, { age: 40, user: "fred" } ],
+      fruits: [ "apple", "banana" ],
+      vegetables: [ "beet", "carrot" ],
+      thing: "hello!",
+      otherThing: null
+    };
+
+    it("extends two objects", function() {
+      var extended = extend(base, source);
+      expect(extended).to.be.eql(expected);
+    });
+  });
+
+  describe("isObject", function() {
+    var fn =_.isObject;
+
+    it("checks if a value is an Object", function() {
+      var Klass = function() {},
+          instance = new Klass();
+
+      expect(fn({})).to.be.eql(true);
+      expect(fn(instance)).to.be.eql(true);
+
+      expect(fn([])).to.be.eql(false);
+      expect(fn(function() {})).to.be.eql(false);
+      expect(fn(10)).to.be.eql(false);
+      expect(fn("")).to.be.eql(false);
+    });
+  });
+
+  describe("isFunction", function() {
+    var fn =_.isFunction;
+
+    it("checks if a value is a Function", function() {
+      expect(fn(function() {})).to.be.eql(true);
+
+      expect(fn({})).to.be.eql(false);
+      expect(fn([])).to.be.eql(false);
+      expect(fn(10)).to.be.eql(false);
+      expect(fn("")).to.be.eql(false);
+    });
+  });
+
+  describe("isArray", function() {
+    var fn = _.isArray;
+
+    it("checks if a value is an Array", function() {
+      expect(fn([])).to.be.eql(true);
+
+      expect(fn(function() {})).to.be.eql(false);
+      expect(fn({})).to.be.eql(false);
+      expect(fn(10)).to.be.eql(false);
+      expect(fn("")).to.be.eql(false);
+    });
+  });
+
+  describe("isNumber", function() {
+    var fn = _.isNumber;
+
+    it("checks if a value is a Number", function() {
+      expect(fn(10)).to.be.eql(true);
+
+      expect(fn(function() {})).to.be.eql(false);
+      expect(fn({})).to.be.eql(false);
+      expect(fn([])).to.be.eql(false);
+      expect(fn("")).to.be.eql(false);
+    });
+  });
+
+  describe("isString", function() {
+    var fn = _.isString;
+
+    it("checks if a value is a String", function() {
+      expect(fn("")).to.be.eql(true);
+
+      expect(fn(10)).to.be.eql(false);
+      expect(fn(function() {})).to.be.eql(false);
+      expect(fn({})).to.be.eql(false);
+      expect(fn([])).to.be.eql(false);
+    });
+  });
+
+  describe("#pluck", function() {
+    var object = { a: { item: "hello" }, b: { item: "world" } },
+        array = [ { item: "hello" }, { item: "world" } ];
+
+    it("plucks values from a collection", function() {
+      expect(_.pluck(object, "item")).to.be.eql(["hello", "world"]);
+      expect(_.pluck(array, "item")).to.be.eql(["hello", "world"]);
+    });
+  });
+
+  describe("#map", function() {
+    var object = { a: { item: "hello" }, b: { item: "world" } },
+        array = [ { item: "hello" }, { item: "world" } ];
+
+    var fn = function(value, key) {
+      return [value, key];
+    };
+
+    it("runs a function over items in a collection", function() {
+      expect(_.map(object, fn)).to.be.eql([
+        [{ item: "hello" }, "a"],
+        [{ item: "world" }, "b"]
+      ]);
+
+      expect(_.map(array, fn)).to.be.eql([
+        [{ item: "hello" }, 0],
+        [{ item: "world" }, 1]
+      ]);
+    });
+
+    it("defaults to the identity function", function() {
+      expect(_.map(array)).to.be.eql(array);
+      expect(_.map(object)).to.be.eql(array);
+    });
+  });
+
+  describe("#invoke", function() {
+    var array = [
+      {
+        name: "bob",
+        toString: function() {
+          return "Hi from " + this.name;
+        }
+      },
+      {
+        name: "dave",
+        toString: function() {
+          return "hello from " + this.name;
+        }
+      }
+    ];
+
+    var object = {
+      bob: {
+        name: "bob",
+        toString: function() {
+          return "Hi from " + this.name;
+        }
+      },
+      dave: {
+        name: "dave",
+        toString: function() {
+          return "hello from " + this.name;
+        }
+      }
+    };
+
+    it("runs a instance function over items in a collection", function() {
+      expect(_.invoke(object, "toString")).to.be.eql([
+        "Hi from bob",
+        "hello from dave"
+      ]);
+
+      expect(_.invoke(array, "toString")).to.be.eql([
+        "Hi from bob",
+        "hello from dave"
+      ]);
+
+      expect(_.invoke([1, 2, 3, 4, 5], Number.prototype.toString)).to.be.eql([
+        "1", "2", "3", "4", "5"
+      ]);
+    });
+  });
+
+  describe("#each", function() {
+    var object = { a: { item: "hello" }, b: { item: "world" } },
+        array = [ { item: "hello" }, { item: "world" } ];
+
+    var fn = function(value, key) {
+      return [value, key];
+    };
+
+    it("runs a function over items in a collection", function() {
+      fn = spy();
+      _.map(object, fn);
+
+      expect(fn).to.be.calledWith(object.a, "a");
+      expect(fn).to.be.calledWith(object.b, "b");
+
+      fn = spy();
+      _.map(array, fn);
+
+      expect(fn).to.be.calledWith(array[0], 0);
+      expect(fn).to.be.calledWith(array[1], 1);
+    });
+  });
+
+  describe("#arity", function() {
+    it("creates a function that only takes a certain # of args", function() {
+      var fn = spy();
+      var one = _.arity(fn, 1);
+      one("one", "two", "three");
+      expect(fn).to.be.calledWith("one");
+    });
+  });
+});