1 files changed, 48 insertions, 0 deletions
diff --git a/node_modules/vue/src/platforms/web/runtime/modules/class.js b/node_modules/vue/src/platforms/web/runtime/modules/class.js
new file mode 100644
index 00000000..29fd2c11
--- /dev/null
+++ b/node_modules/vue/src/platforms/web/runtime/modules/class.js
@@ -0,0 +1,48 @@
+/* @flow */
+
+import {
+  isDef,
+  isUndef
+} from 'shared/util'
+
+import {
+  concat,
+  stringifyClass,
+  genClassForVnode
+} from 'web/util/index'
+
+function updateClass (oldVnode: any, vnode: any) {
+  const el = vnode.elm
+  const data: VNodeData = vnode.data
+  const oldData: VNodeData = oldVnode.data
+  if (
+    isUndef(data.staticClass) &&
+    isUndef(data.class) && (
+      isUndef(oldData) || (
+        isUndef(oldData.staticClass) &&
+        isUndef(oldData.class)
+      )
+    )
+  ) {
+    return
+  }
+
+  let cls = genClassForVnode(vnode)
+
+  // handle transition classes
+  const transitionClass = el._transitionClasses
+  if (isDef(transitionClass)) {
+    cls = concat(cls, stringifyClass(transitionClass))
+  }
+
+  // set the class
+  if (cls !== el._prevClass) {
+    el.setAttribute('class', cls)
+    el._prevClass = cls
+  }
+}
+
+export default {
+  create: updateClass,
+  update: updateClass
+}