From c92e24b7e1c8cd102668a7ce0860312d7a06965d Mon Sep 17 00:00:00 2001
From: Pat Cavit <github@patcavit.com>
Date: Fri, 5 Aug 2016 14:03:34 -0700
Subject: [PATCH] render clears non-mithril dom nodes

---
 api/mount.js                |  1 -
 render/render.js            |  7 ++++++-
 render/tests/index.html     |  1 +
 render/tests/test-render.js | 24 ++++++++++++++++++++++++
 4 files changed, 31 insertions(+), 2 deletions(-)
 create mode 100644 render/tests/test-render.js

diff --git a/api/mount.js b/api/mount.js
index cc16c81f..0465c4c7 100644
--- a/api/mount.js
+++ b/api/mount.js
@@ -1,7 +1,6 @@
 "use strict"
 
 var Vnode = require("../render/vnode")
-var coreRenderer = require("../render/render")
 var autoredraw = require("../api/autoredraw")
 var dummy = {view: function() {}}
 
diff --git a/render/render.js b/render/render.js
index 906291cb..5a83c388 100644
--- a/render/render.js
+++ b/render/render.js
@@ -514,7 +514,12 @@ module.exports = function($window) {
 	function render(dom, vnodes) {
 		var hooks = []
 		var active = $doc.activeElement
-		if (dom.vnodes == null) dom.vnodes = []
+		
+		// First time rendering into a node clears it out
+		if (dom.vnodes == null) {
+			dom.vnodes = []
+			dom.textContent = "";
+		}
 
 		if (!(vnodes instanceof Array)) vnodes = [vnodes]
 		updateNodes(dom, dom.vnodes, Vnode.normalizeChildren(vnodes), hooks, null, undefined)
diff --git a/render/tests/index.html b/render/tests/index.html
index 9c58d56b..2b4e8542 100644
--- a/render/tests/index.html
+++ b/render/tests/index.html
@@ -38,6 +38,7 @@
 		<script src="test-input.js"></script>
 		<script src="test-textContent.js"></script>
 		<script src="test-component.js"></script>
+		<script src="test-render.js"></script>
 
 		<script>require("../../ospec/ospec").run()</script>
 	</body>
diff --git a/render/tests/test-render.js b/render/tests/test-render.js
new file mode 100644
index 00000000..60823166
--- /dev/null
+++ b/render/tests/test-render.js
@@ -0,0 +1,24 @@
+"use strict"
+
+var o = require("../../ospec/ospec")
+var domMock = require("../../test-utils/domMock")
+var vdom = require("../../render/render")
+
+o.spec("render", function() {
+	var $window, root, render
+	o.beforeEach(function() {
+		$window = domMock()
+		root = $window.document.createElement("div")
+		render = vdom($window).render
+	})
+
+	o("overwrites existing content", function() {
+		var vnodes = [{tag: "a", text: null}]
+
+		root.appendChild($window.document.createElement("div"));
+
+		render(root, vnodes)
+
+		o(root.childNodes.length).equals(1)
+	})
+})