diff --git a/js/lib/when-2.0.0.js b/js/lib/when-2.4.0.js
similarity index 61%
rename from js/lib/when-2.0.0.js
rename to js/lib/when-2.4.0.js
index 78249532..aa386275 100644
--- a/js/lib/when-2.0.0.js
+++ b/js/lib/when-2.4.0.js
@@ -9,27 +9,30 @@
  *
  * @author Brian Cavalier
  * @author John Hann
- * @version 2.0.0
+ * @version 2.4.0
  */
-(function(define) { 'use strict';
-define(function () {
+(function(define, global) { 'use strict';
+define(function (require) {
 
 	// Public API
 
-	when.defer     = defer;      // Create a deferred
+	when.promise   = promise;    // Create a pending promise
 	when.resolve   = resolve;    // Create a resolved promise
 	when.reject    = reject;     // Create a rejected promise
+	when.defer     = defer;      // Create a {promise, resolver} pair
 
 	when.join      = join;       // Join 2 or more promises
 
 	when.all       = all;        // Resolve a list of promises
 	when.map       = map;        // Array.map() for promises
 	when.reduce    = reduce;     // Array.reduce() for promises
+	when.settle    = settle;     // Settle a list of promises
 
 	when.any       = any;        // One-winner race
 	when.some      = some;       // Multi-winner race
 
-	when.isPromise = isPromise;  // Determine if a thing is a promise
+	when.isPromise = isPromiseLike;  // DEPRECATED: use isPromiseLike
+	when.isPromiseLike = isPromiseLike; // Is something promise-like, aka thenable
 
 	/**
 	 * Register an observer for a promise or immediate value.
@@ -57,13 +60,35 @@ define(function () {
 	 * a trusted when.js promise.  Any other duck-typed promise is considered
 	 * untrusted.
 	 * @constructor
+	 * @param {function} sendMessage function to deliver messages to the promise's handler
+	 * @param {function?} inspect function that reports the promise's state
 	 * @name Promise
 	 */
-	function Promise(then) {
-		this.then = then;
+	function Promise(sendMessage, inspect) {
+		this._message = sendMessage;
+		this.inspect = inspect;
 	}
 
 	Promise.prototype = {
+		/**
+		 * Register handlers for this promise.
+		 * @param [onFulfilled] {Function} fulfillment handler
+		 * @param [onRejected] {Function} rejection handler
+		 * @param [onProgress] {Function} progress handler
+		 * @return {Promise} new Promise
+		 */
+		then: function(onFulfilled, onRejected, onProgress) {
+			/*jshint unused:false*/
+			var args, sendMessage;
+
+			args = arguments;
+			sendMessage = this._message;
+
+			return _promise(function(resolve, reject, notify) {
+				sendMessage('when', args, resolve, notify);
+			}, this._status && this._status.observed());
+		},
+
 		/**
 		 * Register a rejection handler.  Shortcut for .then(undefined, onRejected)
 		 * @param {function?} onRejected
@@ -84,9 +109,7 @@ define(function () {
 		 * @returns {Promise}
 		 */
 		ensure: function(onFulfilledOrRejected) {
-			var self = this;
-
-			return this.then(injectHandler, injectHandler).yield(self);
+			return this.then(injectHandler, injectHandler)['yield'](this);
 
 			function injectHandler() {
 				return resolve(onFulfilledOrRejected());
@@ -107,6 +130,16 @@ define(function () {
 			});
 		},
 
+		/**
+		 * Runs a side effect when this promise fulfills, without changing the
+		 * fulfillment value.
+		 * @param {function} onFulfilledSideEffect
+		 * @returns {Promise}
+		 */
+		tap: function(onFulfilledSideEffect) {
+			return this.then(onFulfilledSideEffect)['yield'](this);
+		},
+
 		/**
 		 * Assumes that this promise will fulfill with an array, and arranges
 		 * for the onFulfilled to be called with the array as its argument list
@@ -162,13 +195,16 @@ define(function () {
 	}
 
 	/**
-	 * Creates a new Deferred with fully isolated resolver and promise parts,
-	 * either or both of which may be given out safely to consumers.
+	 * Creates a {promise, resolver} pair, either or both of which
+	 * may be given out safely to consumers.
 	 * The resolver has resolve, reject, and progress.  The promise
-	 * only has then.
+	 * has then plus extended promise API.
 	 *
 	 * @return {{
 	 * promise: Promise,
+	 * resolve: function:Promise,
+	 * reject: function:Promise,
+	 * notify: function:Promise
 	 * resolver: {
 	 *	resolve: function:Promise,
 	 *	reject: function:Promise,
@@ -216,12 +252,26 @@ define(function () {
 
 	/**
 	 * Creates a new promise whose fate is determined by resolver.
-	 * @private (for now)
 	 * @param {function} resolver function(resolve, reject, notify)
 	 * @returns {Promise} promise whose fate is determine by resolver
 	 */
 	function promise(resolver) {
-		var value, handlers = [];
+		return _promise(resolver, monitorApi.PromiseStatus && monitorApi.PromiseStatus());
+	}
+
+	/**
+	 * Creates a new promise, linked to parent, whose fate is determined
+	 * by resolver.
+	 * @param {function} resolver function(resolve, reject, notify)
+	 * @param {Promise?} status promise from which the new promise is begotten
+	 * @returns {Promise} promise whose fate is determine by resolver
+	 * @private
+	 */
+	function _promise(resolver, status) {
+		var self, value, consumers = [];
+
+		self = new Promise(_message, inspect);
+		self._status = status;
 
 		// Call the provider resolver to seal the promise's fate
 		try {
@@ -231,29 +281,34 @@ define(function () {
 		}
 
 		// Return the promise
-		return new Promise(then);
+		return self;
 
 		/**
-		 * Register handlers for this promise.
-		 * @param [onFulfilled] {Function} fulfillment handler
-		 * @param [onRejected] {Function} rejection handler
-		 * @param [onProgress] {Function} progress handler
-		 * @return {Promise} new Promise
+		 * Private message delivery. Queues and delivers messages to
+		 * the promise's ultimate fulfillment value or rejection reason.
+		 * @private
+		 * @param {String} type
+		 * @param {Array} args
+		 * @param {Function} resolve
+		 * @param {Function} notify
 		 */
-		function then(onFulfilled, onRejected, onProgress) {
-			return promise(function(resolve, reject, notify) {
-				handlers
-				// Call handlers later, after resolution
-				? handlers.push(function(value) {
-					value.then(onFulfilled, onRejected, onProgress)
-						.then(resolve, reject, notify);
-				})
-				// Call handlers soon, but not in the current stack
-				: enqueue(function() {
-					value.then(onFulfilled, onRejected, onProgress)
-						.then(resolve, reject, notify);
-				});
-			});
+		function _message(type, args, resolve, notify) {
+			consumers ? consumers.push(deliver) : enqueue(function() { deliver(value); });
+
+			function deliver(p) {
+				p._message(type, args, resolve, notify);
+			}
+		}
+
+		/**
+		 * Returns a snapshot of the promise's state at the instant inspect()
+		 * is called. The returned object is not live and will not update as
+		 * the promise's state changes.
+		 * @returns {{ state:String, value?:*, reason?:* }} status snapshot
+		 *  of the promise.
+		 */
+		function inspect() {
+			return value ? value.inspect() : toPendingState();
 		}
 
 		/**
@@ -262,14 +317,17 @@ define(function () {
 		 * @param {*|Promise} val resolution value
 		 */
 		function promiseResolve(val) {
-			if(!handlers) {
+			if(!consumers) {
 				return;
 			}
 
 			value = coerce(val);
-			scheduleHandlers(handlers, value);
+			scheduleConsumers(consumers, value);
+			consumers = undef;
 
-			handlers = undef;
+			if(status) {
+				updateStatus(value, status);
+			}
 		}
 
 		/**
@@ -285,27 +343,90 @@ define(function () {
 		 * @param {*} update progress event payload to pass to all listeners
 		 */
 		function promiseNotify(update) {
-			if(handlers) {
-				scheduleHandlers(handlers, progressing(update));
+			if(consumers) {
+				scheduleConsumers(consumers, progressed(update));
 			}
 		}
 	}
 
+	/**
+	 * Creates a fulfilled, local promise as a proxy for a value
+	 * NOTE: must never be exposed
+	 * @param {*} value fulfillment value
+	 * @returns {Promise}
+	 */
+	function fulfilled(value) {
+		return near(
+			new NearFulfilledProxy(value),
+			function() { return toFulfilledState(value); }
+		);
+	}
+
+	/**
+	 * Creates a rejected, local promise with the supplied reason
+	 * NOTE: must never be exposed
+	 * @param {*} reason rejection reason
+	 * @returns {Promise}
+	 */
+	function rejected(reason) {
+		return near(
+			new NearRejectedProxy(reason),
+			function() { return toRejectedState(reason); }
+		);
+	}
+
+	/**
+	 * Creates a near promise using the provided proxy
+	 * NOTE: must never be exposed
+	 * @param {object} proxy proxy for the promise's ultimate value or reason
+	 * @param {function} inspect function that returns a snapshot of the
+	 *  returned near promise's state
+	 * @returns {Promise}
+	 */
+	function near(proxy, inspect) {
+		return new Promise(function (type, args, resolve) {
+			try {
+				resolve(proxy[type].apply(proxy, args));
+			} catch(e) {
+				resolve(rejected(e));
+			}
+		}, inspect);
+	}
+
+	/**
+	 * Create a progress promise with the supplied update.
+	 * @private
+	 * @param {*} update
+	 * @return {Promise} progress promise
+	 */
+	function progressed(update) {
+		return new Promise(function (type, args, _, notify) {
+			var onProgress = args[2];
+			try {
+				notify(typeof onProgress === 'function' ? onProgress(update) : update);
+			} catch(e) {
+				notify(e);
+			}
+		});
+	}
+
 	/**
 	 * Coerces x to a trusted Promise
 	 *
 	 * @private
 	 * @param {*} x thing to coerce
-	 * @returns {Promise} Guaranteed to return a trusted Promise.  If x
+	 * @returns {*} Guaranteed to return a trusted Promise.  If x
 	 *   is trusted, returns x, otherwise, returns a new, trusted, already-resolved
 	 *   Promise whose resolution value is:
 	 *   * the resolution value of x if it's a foreign promise, or
 	 *   * x if it's a value
 	 */
 	function coerce(x) {
-		if(x instanceof Promise) {
+		if (x instanceof Promise) {
 			return x;
-		} else if (x !== Object(x)) {
+		}
+
+		if (!(x === Object(x) && 'then' in x)) {
 			return fulfilled(x);
 		}
 
@@ -332,61 +453,34 @@ define(function () {
 	}
 
 	/**
-	 * Create an already-fulfilled promise for the supplied value
-	 * @private
+	 * Proxy for a near, fulfilled value
 	 * @param {*} value
-	 * @return {Promise} fulfilled promise
+	 * @constructor
 	 */
-	function fulfilled(value) {
-		var self = new Promise(function (onFulfilled) {
-			try {
-				return typeof onFulfilled == 'function'
-					? coerce(onFulfilled(value)) : self;
-			} catch (e) {
-				return rejected(e);
-			}
-		});
-
-		return self;
+	function NearFulfilledProxy(value) {
+		this.value = value;
 	}
 
+	NearFulfilledProxy.prototype.when = function(onResult) {
+		return typeof onResult === 'function' ? onResult(this.value) : this.value;
+	};
+
 	/**
-	 * Create an already-rejected promise with the supplied rejection reason.
-	 * @private
+	 * Proxy for a near rejection
 	 * @param {*} reason
-	 * @return {Promise} rejected promise
+	 * @constructor
 	 */
-	function rejected(reason) {
-		var self = new Promise(function (_, onRejected) {
-			try {
-				return typeof onRejected == 'function'
-					? coerce(onRejected(reason)) : self;
-			} catch (e) {
-				return rejected(e);
-			}
-		});
-
-		return self;
+	function NearRejectedProxy(reason) {
+		this.reason = reason;
 	}
 
-	/**
-	 * Create a progress promise with the supplied update.
-	 * @private
-	 * @param {*} update
-	 * @return {Promise} progress promise
-	 */
-	function progressing(update) {
-		var self = new Promise(function (_, __, onProgress) {
-			try {
-				return typeof onProgress == 'function'
-					? progressing(onProgress(update)) : self;
-			} catch (e) {
-				return progressing(e);
-			}
-		});
-
-		return self;
-	}
+	NearRejectedProxy.prototype.when = function(_, onError) {
+		if(typeof onError === 'function') {
+			return onError(this.reason);
+		} else {
+			throw this.reason;
+		}
+	};
 
 	/**
 	 * Schedule a task that will process a list of handlers
@@ -395,7 +489,7 @@ define(function () {
 	 * @param {Array} handlers queue of handlers to execute
 	 * @param {*} value passed as the only arg to each handler
 	 */
-	function scheduleHandlers(handlers, value) {
+	function scheduleConsumers(handlers, value) {
 		enqueue(function() {
 			var handler, i = 0;
 			while (handler = handlers[i++]) {
@@ -404,14 +498,23 @@ define(function () {
 		});
 	}
 
+	function updateStatus(value, status) {
+		value.then(statusFulfilled, statusRejected);
+
+		function statusFulfilled() { status.fulfilled(); }
+		function statusRejected(r) { status.rejected(r); }
+	}
+
 	/**
-	 * Determines if promiseOrValue is a promise or not
-	 *
-	 * @param {*} promiseOrValue anything
-	 * @returns {boolean} true if promiseOrValue is a {@link Promise}
+	 * Determines if x is promise-like, i.e. a thenable object
+	 * NOTE: Will return true for *any thenable object*, and isn't truly
+	 * safe, since it may attempt to access the `then` property of x (i.e.
+	 *  clever/malicious getters may do weird things)
+	 * @param {*} x anything
+	 * @returns {boolean} true if x is promise-like
 	 */
-	function isPromise(promiseOrValue) {
-		return promiseOrValue && typeof promiseOrValue.then === 'function';
+	function isPromiseLike(x) {
+		return x && typeof x.then === 'function';
 	}
 
 	/**
@@ -423,17 +526,15 @@ define(function () {
 	 * @param {Array} promisesOrValues array of anything, may contain a mix
 	 *      of promises and values
 	 * @param howMany {number} number of promisesOrValues to resolve
-	 * @param {function?} [onFulfilled] resolution handler
-	 * @param {function?} [onRejected] rejection handler
-	 * @param {function?} [onProgress] progress handler
+	 * @param {function?} [onFulfilled] DEPRECATED, use returnedPromise.then()
+	 * @param {function?} [onRejected] DEPRECATED, use returnedPromise.then()
+	 * @param {function?} [onProgress] DEPRECATED, use returnedPromise.then()
 	 * @returns {Promise} promise that will resolve to an array of howMany values that
 	 *  resolved first, or will reject with an array of
 	 *  (promisesOrValues.length - howMany) + 1 rejection reasons.
 	 */
 	function some(promisesOrValues, howMany, onFulfilled, onRejected, onProgress) {
 
-		checkCallbacks(2, arguments);
-
 		return when(promisesOrValues, function(promisesOrValues) {
 
 			return promise(resolveSome).then(onFulfilled, onRejected, onProgress);
@@ -457,7 +558,7 @@ define(function () {
 					rejectOne = function(reason) {
 						reasons.push(reason);
 						if(!--toReject) {
-							fulfillOne = rejectOne = noop;
+							fulfillOne = rejectOne = identity;
 							reject(reasons);
 						}
 					};
@@ -466,7 +567,7 @@ define(function () {
 						// This orders the values based on promise resolution order
 						values.push(val);
 						if (!--toResolve) {
-							fulfillOne = rejectOne = noop;
+							fulfillOne = rejectOne = identity;
 							resolve(values);
 						}
 					};
@@ -496,9 +597,9 @@ define(function () {
 	 *
 	 * @param {Array|Promise} promisesOrValues array of anything, may contain a mix
 	 *      of {@link Promise}s and values
-	 * @param {function?} [onFulfilled] resolution handler
-	 * @param {function?} [onRejected] rejection handler
-	 * @param {function?} [onProgress] progress handler
+	 * @param {function?} [onFulfilled] DEPRECATED, use returnedPromise.then()
+	 * @param {function?} [onRejected] DEPRECATED, use returnedPromise.then()
+	 * @param {function?} [onProgress] DEPRECATED, use returnedPromise.then()
 	 * @returns {Promise} promise that will resolve to the value that resolved first, or
 	 * will reject with an array of all rejected inputs.
 	 */
@@ -519,14 +620,13 @@ define(function () {
 	 *
 	 * @param {Array|Promise} promisesOrValues array of anything, may contain a mix
 	 *      of {@link Promise}s and values
-	 * @param {function?} [onFulfilled] resolution handler
-	 * @param {function?} [onRejected] rejection handler
-	 * @param {function?} [onProgress] progress handler
+	 * @param {function?} [onFulfilled] DEPRECATED, use returnedPromise.then()
+	 * @param {function?} [onRejected] DEPRECATED, use returnedPromise.then()
+	 * @param {function?} [onProgress] DEPRECATED, use returnedPromise.then()
 	 * @returns {Promise}
 	 */
 	function all(promisesOrValues, onFulfilled, onRejected, onProgress) {
-		checkCallbacks(1, arguments);
-		return map(promisesOrValues, identity).then(onFulfilled, onRejected, onProgress);
+		return _map(promisesOrValues, identity).then(onFulfilled, onRejected, onProgress);
 	}
 
 	/**
@@ -535,28 +635,49 @@ define(function () {
 	 * have fulfilled, or will reject when *any one* of the input promises rejects.
 	 */
 	function join(/* ...promises */) {
-		return map(arguments, identity);
+		return _map(arguments, identity);
 	}
 
 	/**
-	 * Traditional map function, similar to `Array.prototype.map()`, but allows
-	 * input to contain {@link Promise}s and/or values, and mapFunc may return
-	 * either a value or a {@link Promise}
-	 *
-	 * @param {Array|Promise} array array of anything, may contain a mix
-	 *      of {@link Promise}s and values
-	 * @param {function} mapFunc mapping function mapFunc(value) which may return
-	 *      either a {@link Promise} or value
-	 * @returns {Promise} a {@link Promise} that will resolve to an array containing
-	 *      the mapped output values.
+	 * Settles all input promises such that they are guaranteed not to
+	 * be pending once the returned promise fulfills. The returned promise
+	 * will always fulfill, except in the case where `array` is a promise
+	 * that rejects.
+	 * @param {Array|Promise} array or promise for array of promises to settle
+	 * @returns {Promise} promise that always fulfills with an array of
+	 *  outcome snapshots for each input promise.
+	 */
+	function settle(array) {
+		return _map(array, toFulfilledState, toRejectedState);
+	}
+
+	/**
+	 * Promise-aware array map function, similar to `Array.prototype.map()`,
+	 * but input array may contain promises or values.
+	 * @param {Array|Promise} array array of anything, may contain promises and values
+	 * @param {function} mapFunc map function which may return a promise or value
+	 * @returns {Promise} promise that will fulfill with an array of mapped values
+	 *  or reject if any input promise rejects.
 	 */
 	function map(array, mapFunc) {
+		return _map(array, mapFunc);
+	}
+
+	/**
+	 * Internal map that allows a fallback to handle rejections
+	 * @param {Array|Promise} array array of anything, may contain promises and values
+	 * @param {function} mapFunc map function which may return a promise or value
+	 * @param {function?} fallback function to handle rejected promises
+	 * @returns {Promise} promise that will fulfill with an array of mapped values
+	 *  or reject if any input promise rejects.
+	 */
+	function _map(array, mapFunc, fallback) {
 		return when(array, function(array) {
 
-			return promise(resolveMap);
+			return _promise(resolveMap);
 
 			function resolveMap(resolve, reject, notify) {
-				var results, len, toResolve, resolveOne, i;
+				var results, len, toResolve, i;
 
 				// Since we know the resulting length, we can preallocate the results
 				// array to avoid array expansions.
@@ -565,27 +686,28 @@ define(function () {
 
 				if(!toResolve) {
 					resolve(results);
-				} else {
+					return;
+				}
 
-					resolveOne = function(item, i) {
-						when(item, mapFunc).then(function(mapped) {
-							results[i] = mapped;
-
-							if(!--toResolve) {
-								resolve(results);
-							}
-						}, reject, notify);
-					};
-
-					// Since mapFunc may be async, get all invocations of it into flight
-					for(i = 0; i < len; i++) {
-						if(i in array) {
-							resolveOne(array[i], i);
-						} else {
-							--toResolve;
-						}
+				// Since mapFunc may be async, get all invocations of it into flight
+				for(i = 0; i < len; i++) {
+					if(i in array) {
+						resolveOne(array[i], i);
+					} else {
+						--toResolve;
 					}
 				}
+
+				function resolveOne(item, i) {
+					when(item, mapFunc, fallback).then(function(mapped) {
+						results[i] = mapped;
+						notify(mapped);
+
+						if(!--toResolve) {
+							resolve(results);
+						}
+					}, reject);
+				}
 			}
 		});
 	}
@@ -625,12 +747,46 @@ define(function () {
 		});
 	}
 
+	// Snapshot states
+
+	/**
+	 * Creates a fulfilled state snapshot
+	 * @private
+	 * @param {*} x any value
+	 * @returns {{state:'fulfilled',value:*}}
+	 */
+	function toFulfilledState(x) {
+		return { state: 'fulfilled', value: x };
+	}
+
+	/**
+	 * Creates a rejected state snapshot
+	 * @private
+	 * @param {*} x any reason
+	 * @returns {{state:'rejected',reason:*}}
+	 */
+	function toRejectedState(x) {
+		return { state: 'rejected', reason: x };
+	}
+
+	/**
+	 * Creates a pending state snapshot
+	 * @private
+	 * @returns {{state:'pending'}}
+	 */
+	function toPendingState() {
+		return { state: 'pending' };
+	}
+
 	//
-	// Utilities, etc.
+	// Internals, utilities, etc.
 	//
 
 	var reduceArray, slice, fcall, nextTick, handlerQueue,
-		timeout, funcProto, call, arrayProto, undef;
+		setTimeout, funcProto, call, arrayProto, monitorApi,
+		cjsRequire, undef;
+
+	cjsRequire = require;
 
 	//
 	// Shared handler queue processing
@@ -648,20 +804,13 @@ define(function () {
 	 */
 	function enqueue(task) {
 		if(handlerQueue.push(task) === 1) {
-			scheduleDrainQueue();
+			nextTick(drainQueue);
 		}
 	}
 
 	/**
-	 * Schedule the queue to be drained in the next tick.
-	 */
-	function scheduleDrainQueue() {
-		nextTick(drainQueue);
-	}
-
-	/**
-	 * Drain the handler queue entirely or partially, being careful to allow
-	 * the queue to be extended while it is being processed, and to continue
+	 * Drain the handler queue entirely, being careful to allow the
+	 * queue to be extended while it is being processed, and to continue
 	 * processing until it is truly empty.
 	 */
 	function drainQueue() {
@@ -674,20 +823,36 @@ define(function () {
 		handlerQueue = [];
 	}
 
-	//
-	// Capture function and array utils
-	//
-	/*global setImmediate:true*/
+	// capture setTimeout to avoid being caught by fake timers
+	// used in time based tests
+	setTimeout = global.setTimeout;
 
-	// capture setTimeout to avoid being caught by fake timers used in time based tests
-	timeout = setTimeout;
-	nextTick = typeof setImmediate === 'function'
-		? typeof window === 'undefined'
-			? setImmediate
-			: setImmediate.bind(window)
-		: typeof process === 'object'
-			? process.nextTick
-			: function(task) { timeout(task, 0); };
+	// Allow attaching the monitor to when() if env has no console
+	monitorApi = typeof console != 'undefined' ? console : when;
+
+	// Prefer setImmediate or MessageChannel, cascade to node,
+	// vertx and finally setTimeout
+	/*global setImmediate,MessageChannel,process*/
+	if (typeof setImmediate === 'function') {
+		nextTick = setImmediate.bind(global);
+	} else if(typeof MessageChannel !== 'undefined') {
+		var channel = new MessageChannel();
+		channel.port1.onmessage = drainQueue;
+		nextTick = function() { channel.port2.postMessage(0); };
+	} else if (typeof process === 'object' && process.nextTick) {
+		nextTick = process.nextTick;
+	} else {
+		try {
+			// vert.x 1.x || 2.x
+			nextTick = cjsRequire('vertx').runOnLoop || cjsRequire('vertx').runOnContext;
+		} catch(ignore) {
+			nextTick = function(t) { setTimeout(t, 0); };
+		}
+	}
+
+	//
+	// Capture/polyfill function and array utils
+	//
 
 	// Safe function calls
 	funcProto = Function.prototype;
@@ -748,40 +913,10 @@ define(function () {
 			return reduced;
 		};
 
-	//
-	// Utility functions
-	//
-
-	/**
-	 * Helper that checks arrayOfCallbacks to ensure that each element is either
-	 * a function, or null or undefined.
-	 * @private
-	 * @param {number} start index at which to start checking items in arrayOfCallbacks
-	 * @param {Array} arrayOfCallbacks array to check
-	 * @throws {Error} if any element of arrayOfCallbacks is something other than
-	 * a functions, null, or undefined.
-	 */
-	function checkCallbacks(start, arrayOfCallbacks) {
-		// TODO: Promises/A+ update type checking and docs
-		var arg, i = arrayOfCallbacks.length;
-
-		while(i > start) {
-			arg = arrayOfCallbacks[--i];
-
-			if (arg != null && typeof arg != 'function') {
-				throw new Error('arg '+i+' must be a function');
-			}
-		}
-	}
-
-	function noop() {}
-
 	function identity(x) {
 		return x;
 	}
 
 	return when;
 });
-})(
-	typeof define === 'function' && define.amd ? define : function (factory) { module.exports = factory(); }
-);
+})(typeof define === 'function' && define.amd ? define : function (factory) { module.exports = factory(require); }, this);
diff --git a/js/package.json b/js/package.json
index 8a4e425d..9134bbc0 100644
--- a/js/package.json
+++ b/js/package.json
@@ -16,7 +16,7 @@
   "dependencies": {
     "bane": "~1.0.0",
     "faye-websocket": "~0.4.4",
-    "when": "~2.0.0"
+    "when": "~2.4.0"
   },
   "devDependencies": {
     "buster": "~0.6.12",