fix: polyfill Element.matches for IE < 11 (#1230)

fixes #1223

packages/test-utils/src/mount.js

@@ -5,6 +5,7 @@ import { throwIfInstancesThrew, addGlobalErrorHandler } from './error'
 import { mergeOptions } from 'shared/merge-options'
 import config from './config'
 import warnIfNoWindow from './warn-if-no-window'
+import polyfill from './polyfill'
 import createWrapper from './create-wrapper'
 import createLocalVue from './create-local-vue'
 import { validateOptions } from 'shared/validate-options'
@@ -15,6 +16,8 @@ Vue.config.devtools = false
 export default function mount(component, options = {}) {
   warnIfNoWindow()
 
+  polyfill()
+
   addGlobalErrorHandler(Vue)
 
   const _Vue = createLocalVue(options.localVue)

packages/test-utils/src/polyfill.js

@@ -0,0 +1,9 @@
+export default function polyfill() {
+  // Polyfill `Element.matches()` for IE and older versions of Chrome:
+  // https://developer.mozilla.org/en-US/docs/Web/API/Element/matches#Polyfill
+  if (!Element.prototype.matches) {
+    Element.prototype.matches =
+      Element.prototype.msMatchesSelector ||
+      Element.prototype.webkitMatchesSelector
+  }
+}