Added promise support

ext/dispose.js

@@ -11,7 +11,7 @@ var callable   = require('es5-ext/object/valid-callable')
 extensions.dispose = function (dispose, conf, options) {
 	var del;
 	callable(dispose);
-	if (options.async && extensions.async) {
+	if ((options.async && extensions.async) || (options.promise && extensions.promise)) {
 		conf.on('deleteasync', del = function (id, result) {
 			apply.call(dispose, null, slice.call(result.args, 1));
 		});

ext/promise.js

@@ -0,0 +1,50 @@
+// Support for functions returning promise
+
+'use strict';
+
+var nextTick = require('next-tick')
+
+  , create = Object.create;
+
+require('../lib/registered-extensions').promise = function (tbi, conf) {
+	var cache = create(null);
+
+	// After not from cache call
+	conf.on('set', function (id, __, promise) {
+		promise.then(function () {
+			// nextTick avoids error interception
+			nextTick(function () {
+				cache[id] = promise;
+				conf.emit('setasync', id, 1);
+			});
+		}, function () {
+			nextTick(function () {
+				conf.delete(id);
+			});
+		});
+	});
+
+	// From cache (sync)
+	conf.on('get', function (id, args, context) {
+		conf.emit('getasync', id, args, context);
+	});
+
+	// On delete
+	conf.on('delete', function (id) {
+		var result;
+		// If false, we don't have value yet, so we assume that intention is not
+		// to memoize this call. After value is obtained we don't cache it but
+		// gracefully pass to callback
+		if (!cache[id]) return;
+		result = cache[id];
+		delete cache[id];
+		conf.emit('deleteasync', id, result);
+	});
+
+	// On clear
+	conf.on('clear', function () {
+		var oldCache = cache;
+		cache = create(null);
+		conf.emit('clearasync', oldCache);
+	});
+};