diff --git a/polyfills/promise.js b/polyfills/promise.js
index 330dc4a3..f42c9d36 100644
--- a/polyfills/promise.js
+++ b/polyfills/promise.js
@@ -26,16 +26,14 @@
     // job queues, within a certain queue strict FIFO is required.  See ES5.1
     // https://www.ecma-international.org/ecma-262/6.0/#sec-jobs-and-job-queues:
     // "The PendingJob records from a single Job Queue are always initiated in
-    // FIFO order. This specification does not define the order in which multiple
-    // Job Queues are serviced."
-    var queueHead = null;
-    var queueTail = null;
+    // FIFO order. This specification does not define the order in which
+    // multiple Job Queues are serviced."
+    var queueHead = null, queueTail = null;
     function enqueueJob(job) {
         if (queueHead) {
-            queueTail.next = job;
-            queueTail = job;
+            queueTail.next = job; queueTail = job;
         } else {
-            queueHead = queueTail = job;
+            queueHead = job; queueTail = job;
         }
     }
     function dequeueJob() {
@@ -60,11 +58,16 @@
         });
     }
 
-    // Promise detection (plain or subclassed Promise), in spec has [[PromiseState]]
-    // internal slot which isn't affected by Proxy behaviors etc.
+    // Promise detection (plain or subclassed Promise), in spec has
+    // [[PromiseState]] internal slot which isn't affected by Proxy
+    // behaviors etc.
     var symMarker = Symbol('promise');
-    function isPromise(p) { return p !== null && typeof p === 'object' && symMarker in p; }
-    function requirePromise(p) { if (!isPromise(p)) { throw new TypeError('Promise required'); } }
+    function isPromise(p) {
+        return p !== null && typeof p === 'object' && symMarker in p;
+    }
+    function requirePromise(p) {
+        if (!isPromise(p)) { throw new TypeError('Promise required'); }
+    }
 
     // Raw fulfill/reject operations, assume resolution processing done.
     function doFulfill(p, val) {
@@ -73,7 +76,12 @@
         var reactions = p.fulfillReactions;
         delete p.fulfillReactions; delete p.rejectReactions;
         reactions.forEach(function (r) {
-            enqueueJob({ handler: r.handler, resolve: r.resolve, reject: r.reject, value: val });  // only value is new
+            enqueueJob({
+                handler: r.handler,
+                resolve: r.resolve,
+                reject: r.reject,
+                value: val
+            });  // only value is new
         });
     }
     function doReject(p, val) {
@@ -82,7 +90,12 @@
         var reactions = p.rejectReactions;
         delete p.fulfillReactions; delete p.rejectReactions;
         reactions.forEach(function (r) {
-            enqueueJob({ handler: r.handler, resolve: r.resolve, reject: r.reject, value: val });  // only value is new
+            enqueueJob({
+                handler: r.handler,
+                resolve: r.resolve,
+                reject: r.reject,
+                value: val
+            });  // only value is new
         });
     }
 
@@ -94,30 +107,40 @@
     // to forcibly resolve/fulfill/reject a Promise regardless of extant
     // resolve/reject functions.
     function getResolutionFunctions(p) {
+        // In ES2015 the resolve/reject functions have a shared 'state' object
+        // with a [[AlreadyResolved]] slot.  Here we use an in-scope variable.
+        var alreadyResolved = false;
         var reject = function (err) {
-            if (reject.state.alreadyResolved) { return; }
-            reject.state.alreadyResolved = true;  // neutralize this resolve/reject pair
+            if (alreadyResolved) { return; }
+            alreadyResolved = true;  // neutralize resolve/reject
             if (p.state !== void 0) { return; }
             doReject(p, err);
         };
         var resolve = function (val) {
-            if (resolve.state.alreadyResolved) { return; }
-            resolve.state.alreadyResolved = true;  // neutralize this resolve/reject pair
+            if (alreadyResolved) { return; }
+            alreadyResolved = true;  // neutralize resolve/reject
             if (p.state !== void 0) { return; }
-            if (val === p) { return doReject(p, new TypeError('self resolution')); }
+            if (val === p) {
+                return doReject(p, new TypeError('self resolution'));
+            }
             try {
-                var then = (val !== null && typeof val === 'object' && val.then);
+                var then = (val !== null && typeof val === 'object' &&
+                            val.then);
                 if (typeof then === 'function') {
                     var t = getResolutionFunctions(p);
-                    return enqueueJob({ thenable: val, then: then, resolve: t.resolve, reject: t.reject });
-                    // old resolve/reject is neutralized, only the new pair is live
+                    return enqueueJob({
+                        thenable: val,
+                        then: then,
+                        resolve: t.resolve,
+                        reject: t.reject
+                    });
+                    // old resolve/reject is neutralized, only new pair is live
                 }
                 return doFulfill(p, val);
             } catch (e) {
                 return doReject(p, e);
             }
         };
-        reject.state = resolve.state = {};  // shared state for [[AlreadyResolved]]
         return { resolve: resolve, reject: reject };
     }
 
@@ -152,11 +175,15 @@
 
     // %Promise% constructor.
     var cons = function Promise(executor) {
-        if (!new.target) { throw new TypeError('Promise must be called as a constructor'); }
-        if (typeof executor !== 'function') { throw new TypeError('executor must be callable'); }
+        if (!new.target) {
+            throw new TypeError('Promise must be called as a constructor');
+        }
+        if (typeof executor !== 'function') {
+            throw new TypeError('executor must be callable');
+        }
         var _this = this;
         this[symMarker] = true;
-        def(this, 'state', void 0);   // undefined (pending), true (fulfilled), false (rejected)
+        def(this, 'state', void 0);   // undefined (pending), true/false
         def(this, 'value', void 0);
         def(this, 'fulfillReactions', []);
         def(this, 'rejectReactions', []);
@@ -168,7 +195,7 @@
         }
     };
     var proto = cons.prototype;
-    Object.defineProperty(cons, 'prototype', { writable: false, enumerable: false, configurable: false });
+    def(cons, 'prototype', proto, '');
 
     // %Promise%.resolve().
     // XXX: direct handling
@@ -186,28 +213,31 @@
     // %Promise%.all().
     function all(list) {
         var resolveFn, rejectFn;
-        var p = new Promise(function (resolve, reject) { resolveFn = resolve; rejectFn = reject; });
-        var state = { values: [], remaining: 1, resolve: resolveFn, reject: rejectFn };  // remaining intentionally 1, not 0
+        var p = new Promise(function (resolve, reject) {
+            resolveFn = resolve; rejectFn = reject;
+        });
+        var values = [];
         var index = 0;
+        var remaining = 1;  // remaining intentionally 1, not 0
         list.forEach(function (x) {  // XXX: no iterator support
             var t = Promise.resolve(x);
             var f = function promiseAllElement(val) {
                 var F = promiseAllElement;
-                var S = F.state;
                 if (F.alreadyCalled) { return; }
                 F.alreadyCalled = true;
-                S.values[F.index] = val;
-                if (--S.remaining === 0) {
-                    S.resolve.call(void 0, S.values);
+                values[F.index] = val;
+                if (--remaining === 0) {
+                    resolveFn.call(void 0, values);
                 }
             };
-            f.state = state;
+            // In ES2015 the functions would reference a shared state object
+            // explicitly.  Here the conceptual state is in scope.
             f.index = index++;
-            state.remaining++;
+            remaining++;
             t.then(f, rejectFn);
         });
-        if (--state.remaining === 0) {
-            resolveFn.call(void 0, state.values);
+        if (--remaining === 0) {
+            resolveFn.call(void 0, values);
         }
         return p;
     }
@@ -215,7 +245,9 @@
     // %Promise%.race().
     function race(list) {
         var resolveFn, rejectFn;
-        var p = new Promise(function (resolve, reject) { resolveFn = resolve; rejectFn = reject; });
+        var p = new Promise(function (resolve, reject) {
+            resolveFn = resolve; rejectFn = reject;
+        });
         list.forEach(function (x) {  // XXX: no iterator support
             var t = Promise.resolve(x);
             t.then(resolveFn, rejectFn);
@@ -228,16 +260,36 @@
         // No subclassing support here now, no NewPromiseCapability() handling.
         requirePromise(this);
         var resolveFn, rejectFn;
-        var p = new Promise(function (resolve, reject) { resolveFn = resolve; rejectFn = reject; });
-        onFulfilled = (typeof onFulfilled === 'function' ? onFulfilled : 'Identity');
-        onRejected = (typeof onRejected === 'function' ? onRejected : 'Thrower');
+        var p = new Promise(function (resolve, reject) {
+            resolveFn = resolve; rejectFn = reject;
+        });
+        if (typeof onFulfilled !== 'function') { onFulfilled = 'Identity' }
+        if (typeof onRejected !== 'function') { onRejected = 'Thrower' }
         if (this.state === void 0) {  // pending
-            this.fulfillReactions.push({ handler: onFulfilled, resolve: resolveFn, reject: rejectFn });
-            this.rejectReactions.push({ handler: onRejected, resolve: resolveFn, reject: rejectFn });
+            this.fulfillReactions.push({
+                handler: onFulfilled,
+                resolve: resolveFn,
+                reject: rejectFn
+            });
+            this.rejectReactions.push({
+                handler: onRejected,
+                resolve: resolveFn,
+                reject: rejectFn
+            });
         } else if (this.state) {  // fulfilled
-            enqueueJob({ handler: onFulfilled, resolve: resolveFn, reject: rejectFn, value: this.value });
+            enqueueJob({
+                handler: onFulfilled,
+                resolve: resolveFn,
+                reject: rejectFn,
+                value: this.value
+            });
         } else {  // rejected
-            enqueueJob({ handler: onRejected, resolve: resolveFn, reject: rejectFn, value: this.value });
+            enqueueJob({
+                handler: onRejected,
+                resolve: resolveFn,
+                reject: rejectFn,
+                value: this.value
+            });
         }
         return p;
     }
@@ -268,7 +320,7 @@
         def(proto, 'catch', _catch);
         def(proto, Symbol.toStringTag, 'Promise', 'c');
 
-        // Not part of the actual Promise API, but used to drive the "job queue".
+        // Custom API to drive the "job queue".
         def(cons, 'runQueue', function _runQueueUntilEmpty() {
             while (runQueueEntry()) {}
         });