diff --git a/index.js b/index.js
index 3a0c8e18..8467bd99 100644
--- a/index.js
+++ b/index.js
@@ -1,5 +1,6 @@
 "use strict"
 
+var Promise = require("./promise/promise")
 var m = require("./render/hyperscript")
 var renderService = require("./render/render")(window)
 var redrawService = require("./api/pubsub")()
diff --git a/promise/promise.js b/promise/promise.js
index baf1090b..cf24f387 100644
--- a/promise/promise.js
+++ b/promise/promise.js
@@ -1,98 +1,98 @@
 "use strict"
-{
-function Promise(executor) {
-	if (!(this instanceof Promise)) throw new Error("Promise must be called with `new`")
-	if (typeof executor !== "function") throw new Error("executor must be a function")
-	
-	var self = this, resolvers = [], rejectors = [], resolveCurrent = handler(resolvers, true), rejectCurrent = handler(rejectors, false)
-	var instance = self._instance = {resolvers: resolvers, rejectors: rejectors}
-	var callAsync = typeof setImmediate === "function" ? setImmediate : setTimeout
-	function handler(list, shouldAbsorb) {
-		return function execute(value) {
-			var then
-			try {
-				if (shouldAbsorb && value != null && (typeof value === "object" || typeof value === "function") && typeof (then = value.then) === "function") {
-					if (value === self) throw new TypeError("Promise can't be resolved w/ itself")
-					executeOnce(then.bind(value))
-				}
-				else {
-					callAsync(function() {
-						if (!shouldAbsorb && list.length === 0) console.error("Possible unhandled promise rejection:", value)
-						for (var i = 0; i < list.length; i++) list[i](value)
-						resolvers.length = 0, rejectors.length = 0
-						instance.state = shouldAbsorb
-						instance.retry = function() {execute(value)}
-					}, 0)
-				}
-			}
-			catch (e) {
-				rejectCurrent(e)
-			}
-		}
-	}
-	function executeOnce(then) {
-		var runs = 0
-		function run(fn) {
-			return function(value) {
-				if (runs++ > 0) return
-				fn(value)
-			}
-		}
-		var onerror = run(rejectCurrent)
-		try {then(run(resolveCurrent), onerror)} catch (e) {onerror(e)}
-	}
-	
-	executeOnce(executor)
-}
-Promise.prototype.then = function(onFulfilled, onRejection) {
-	var self = this, instance = self._instance
-	function handle(callback, list, next, state) {
-		list.push(function(value) {
-			if (typeof callback !== "function") next(value)
-			else try {resolveNext(callback(value))} catch (e) {if (rejectNext) rejectNext(e)}
-		})
-		if (typeof instance.retry === "function" && state === instance.state) instance.retry()
-	}
-	var resolveNext, rejectNext
-	var promise = new Promise(function(resolve, reject) {resolveNext = resolve, rejectNext = reject})
-	handle(onFulfilled, instance.resolvers, resolveNext, true), handle(onRejection, instance.rejectors, rejectNext, false)
-	return promise
-}
-Promise.prototype.catch = function(onRejection) {
-	return this.then(null, onRejection)
-}
-Promise.resolve = function(value) {
-	if (value instanceof Promise) return value
-	return new Promise(function(resolve, reject) {resolve(value)})
-}
-Promise.reject = function(value) {
-	return new Promise(function(resolve, reject) {reject(value)})
-}
-Promise.all = function(list) {
-	return new Promise(function(resolve, reject) {
-		var total = list.length, count = 0, values = []
-		for (var i = 0; i < list.length; i++) {
-			new function(i) {
-				function consume(value) {
-					count++
-					values[i] = value
-					if (count === total) resolve(values)
-				}
-				if (list[i] != null && (typeof list[i] === "object" || typeof list[i] === "function") && typeof list[i].then === "function") {
-					list[i].then(consume, reject)
-				}
-				else consume(list[i])
-			}(i)
-		}
-	})
-}
-Promise.race = function(list) {
-	return new Promise(function(resolve, reject) {
-		for (var i = 0; i < list.length; i++) {
-			list[i].then(resolve, reject)
-		}
-	})
-}
 
+if (typeof Promise === "undefined") {
+	var Promise = function(executor) {
+		if (!(this instanceof Promise)) throw new Error("Promise must be called with `new`")
+		if (typeof executor !== "function") throw new TypeError("executor must be a function")
+		
+		var self = this, resolvers = [], rejectors = [], resolveCurrent = handler(resolvers, true), rejectCurrent = handler(rejectors, false)
+		var instance = self._instance = {resolvers: resolvers, rejectors: rejectors}
+		var callAsync = typeof setImmediate === "function" ? setImmediate : setTimeout
+		function handler(list, shouldAbsorb) {
+			return function execute(value) {
+				var then
+				try {
+					if (shouldAbsorb && value != null && (typeof value === "object" || typeof value === "function") && typeof (then = value.then) === "function") {
+						if (value === self) throw new TypeError("Promise can't be resolved w/ itself")
+						executeOnce(then.bind(value))
+					}
+					else {
+						callAsync(function() {
+							if (!shouldAbsorb && list.length === 0) console.error("Possible unhandled promise rejection:", value)
+							for (var i = 0; i < list.length; i++) list[i](value)
+							resolvers.length = 0, rejectors.length = 0
+							instance.state = shouldAbsorb
+							instance.retry = function() {execute(value)}
+						}, 0)
+					}
+				}
+				catch (e) {
+					rejectCurrent(e)
+				}
+			}
+		}
+		function executeOnce(then) {
+			var runs = 0
+			function run(fn) {
+				return function(value) {
+					if (runs++ > 0) return
+					fn(value)
+				}
+			}
+			var onerror = run(rejectCurrent)
+			try {then(run(resolveCurrent), onerror)} catch (e) {onerror(e)}
+		}
+		
+		executeOnce(executor)
+	}
+	Promise.prototype.then = function(onFulfilled, onRejection) {
+		var self = this, instance = self._instance
+		function handle(callback, list, next, state) {
+			list.push(function(value) {
+				if (typeof callback !== "function") next(value)
+				else try {resolveNext(callback(value))} catch (e) {if (rejectNext) rejectNext(e)}
+			})
+			if (typeof instance.retry === "function" && state === instance.state) instance.retry()
+		}
+		var resolveNext, rejectNext
+		var promise = new Promise(function(resolve, reject) {resolveNext = resolve, rejectNext = reject})
+		handle(onFulfilled, instance.resolvers, resolveNext, true), handle(onRejection, instance.rejectors, rejectNext, false)
+		return promise
+	}
+	Promise.prototype.catch = function(onRejection) {
+		return this.then(null, onRejection)
+	}
+	Promise.resolve = function(value) {
+		if (value instanceof Promise) return value
+		return new Promise(function(resolve, reject) {resolve(value)})
+	}
+	Promise.reject = function(value) {
+		return new Promise(function(resolve, reject) {reject(value)})
+	}
+	Promise.all = function(list) {
+		return new Promise(function(resolve, reject) {
+			var total = list.length, count = 0, values = []
+			for (var i = 0; i < list.length; i++) {
+				new function(i) {
+					function consume(value) {
+						count++
+						values[i] = value
+						if (count === total) resolve(values)
+					}
+					if (list[i] != null && (typeof list[i] === "object" || typeof list[i] === "function") && typeof list[i].then === "function") {
+						list[i].then(consume, reject)
+					}
+					else consume(list[i])
+				}(i)
+			}
+		})
+	}
+	Promise.race = function(list) {
+		return new Promise(function(resolve, reject) {
+			for (var i = 0; i < list.length; i++) {
+				list[i].then(resolve, reject)
+			}
+		})
+	}
+}
 module.exports = Promise
-}
\ No newline at end of file