From e24d595a306c4e63d189954c917360946a1de392 Mon Sep 17 00:00:00 2001
From: Blake Simpson <blake.simpson@xyrality.net>
Date: Thu, 13 Feb 2014 15:36:07 +0100
Subject: [PATCH 1/2] Allow _.throttle to function correctly after the system
 time is updated

---
 test/functions.js | 20 ++++++++++++++++++++
 underscore.js     |  2 +-
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/test/functions.js b/test/functions.js
index 14ea934c2..474f615c1 100644
--- a/test/functions.js
+++ b/test/functions.js
@@ -278,6 +278,26 @@
     }, 96);
   });
 
+  asyncTest('throttle continues to function after system time is set backwards', 2, function() {
+    var counter = 0;
+    var incr = function(){ counter++; };
+    var throttledIncr = _.throttle(incr, 100);
+    var origNowFunc = _.now;
+
+    throttledIncr();
+    ok(counter == 1);
+    _.now = function () {
+      return new Date(2013, 0, 1, 1, 1, 1);
+    };
+
+    _.delay(function() {
+      throttledIncr();
+      ok(counter == 2);
+      start();
+      _.now = origNowFunc;
+    }, 200);
+  });
+
   asyncTest('debounce', 1, function() {
     var counter = 0;
     var incr = function(){ counter++; };
diff --git a/underscore.js b/underscore.js
index ca61fdc3a..cb9318910 100644
--- a/underscore.js
+++ b/underscore.js
@@ -695,7 +695,7 @@
       var remaining = wait - (now - previous);
       context = this;
       args = arguments;
-      if (remaining <= 0) {
+      if (remaining <= 0 || remaining > wait) {
         clearTimeout(timeout);
         timeout = null;
         previous = now;

From fa3526055bf662a7f0940a2d930e8021a7abeb1e Mon Sep 17 00:00:00 2001
From: Blake Simpson <blakersim@gmail.com>
Date: Fri, 14 Feb 2014 19:12:09 +0100
Subject: [PATCH 2/2] Add sanity check to _.debounce incase system time is
 moved between calls

---
 test/functions.js | 22 ++++++++++++++++++++++
 underscore.js     |  3 ++-
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/test/functions.js b/test/functions.js
index 474f615c1..a89cc6a73 100644
--- a/test/functions.js
+++ b/test/functions.js
@@ -334,6 +334,28 @@
     _.delay(function(){ equal(counter, 1, 'incr was debounced'); start(); }, 96);
   });
 
+  asyncTest('debounce after system time is set backwards', 2, function() {
+    var counter = 0;
+    var origNowFunc = _.now;
+    var debouncedIncr = _.debounce(function(){
+      counter++;
+    }, 100, true);
+
+    debouncedIncr();
+    equal(counter, 1, 'incr was called immediately');
+
+    _.now = function () {
+      return new Date(2013, 0, 1, 1, 1, 1);
+    };
+
+    _.delay(function() {
+      debouncedIncr();
+      equal(counter, 2, 'incr was debounced successfully');
+      start();
+      _.now = origNowFunc;
+    },200);
+  });
+
   test('once', function() {
     var num = 0;
     var increment = _.once(function(){ num++; });
diff --git a/underscore.js b/underscore.js
index cb9318910..702cb5259 100644
--- a/underscore.js
+++ b/underscore.js
@@ -717,7 +717,8 @@
 
     var later = function() {
       var last = _.now() - timestamp;
-      if (last < wait) {
+
+      if (last < wait && last > 0) {
         timeout = setTimeout(later, wait - last);
       } else {
         timeout = null;