From 7efda2c10bae2babf35c604678c406b065556acc Mon Sep 17 00:00:00 2001
From: Leo Horie <lhorie@klick.com>
Date: Thu, 18 Sep 2014 22:58:59 -0400
Subject: [PATCH] deal with setTimeout properly

---
 mithril.js | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/mithril.js b/mithril.js
index 24cc7581..8c720b90 100644
--- a/mithril.js
+++ b/mithril.js
@@ -366,7 +366,7 @@ Mithril = m = new function app(window, undefined) {
 			m.startComputation()
 			try {return callback.call(object, e)}
 			finally {
-				if (!lastRedrawId) lastRedrawId = -1
+				if (!lastRedrawId) lastRedrawId = -1 //force asynchronous redraw for event handlers, to prevent double redraw in cases like onkeypress+oninput
 				m.endComputation()
 			}
 		}
@@ -439,7 +439,8 @@ Mithril = m = new function app(window, undefined) {
 		return _prop(store)
 	}
 
-	var roots = [], modules = [], controllers = [], lastRedrawId = 0, redrawAgain = false, computePostRedrawHook = null, prevented = false
+	var roots = [], modules = [], controllers = [], lastRedrawId = 0, lastRedrawCallTime = 0, computePostRedrawHook = null, prevented = false
+	var FRAME_BUDGET = 16 //60 frames per second = 1 call per 16 ms
 	m.module = function(root, module) {
 		var index = roots.indexOf(root)
 		if (index < 0) index = roots.length
@@ -463,20 +464,20 @@ Mithril = m = new function app(window, undefined) {
 	m.redraw = function(force) {
 		var cancel = window.cancelAnimationFrame || window.clearTimeout
 		var defer = window.requestAnimationFrame || window.setTimeout
+		//lastRedrawId is a positive number if a second redraw is requested before the next animation frame
+		//lastRedrawId is -1 if the redraw is the first one in a event handler (see #151)
+		//lastRedrawID is null if it's the first redraw and not an event handler
 		if (lastRedrawId && force !== true) {
-			redrawAgain = true
+			//when setTimeout: only reschedule redraw if time between now and previous redraw is bigger than a frame, otherwise keep currently scheduled timeout
+			//when rAF: always reschedule redraw
+			if (new Date - lastRedrawCallTime > FRAME_BUDGET || defer == window.requestAnimationFrame) {
+				if (lastRedrawID > 0) cancel(lastRedrawId)
+				lastRedrawId = defer(redraw, delay)
+			}
 		}
 		else {
 			redraw()
-			lastRedrawId = defer(delay, 16) //60 frames per second = 1 call per 16 ms
-		}
-
-		function delay() {
-			lastRedrawId = null
-			if (redrawAgain) {
-				redrawAgain = false
-				m.redraw()
-			}
+			lastRedrawId = defer(function() {lastRedrawId = null}, delay)
 		}
 	}
 	m.redraw.strategy = m.prop()
@@ -490,6 +491,7 @@ Mithril = m = new function app(window, undefined) {
 			computePostRedrawHook = null
 		}
 		lastRedrawId = null
+		lastRedrawCallTime = new Date
 		m.redraw.strategy("diff")
 	}