feat: allow opting out of stubbed transitions

Author: lmiller1990

src/config.ts

@@ -1,6 +1,6 @@
+import { ComponentPublicInstance } from 'vue'
 import { GlobalMountOptions } from './types'
 import { VueWrapper } from './vueWrapper'
-import { ComponentPublicInstance } from 'vue'
 
 interface GlobalConfigOptions {
   global: GlobalMountOptions
@@ -19,7 +19,7 @@ interface Plugin {
 }
 
 class Pluggable {
-  installedPlugins = [] as Array<Plugin>
+  installedPlugins: Plugin[] = []
 
   install(
     handler: (
@@ -55,7 +55,12 @@ class Pluggable {
 }
 
 export const config: GlobalConfigOptions = {
-  global: {},
+  global: {
+    stubs: {
+      transition: true,
+      'transition-group': true
+    }
+  },
   plugins: {
     VueWrapper: new Pluggable(),
     DOMWrapper: new Pluggable()

src/mount.ts

@@ -350,12 +350,9 @@ export function mount(
   app.mixin(attachEmitListener())
 
   // stubs
-  if (global.stubs || options?.shallow) {
-    stubComponents(global.stubs, options?.shallow)
-  } else {
-    // still apply default stub of Transition and Transition Group
-    stubComponents()
-  }
+  // even if we are using `mount`, we will still
+  // stub out Transition and Transition Group by default.
+  stubComponents(global.stubs, options?.shallow)
 
   // mount the app!
   const vm = app.mount(el)

src/stubs.ts

@@ -92,7 +92,11 @@ export function stubComponents(
     // 1. a HTML tag (div, span...)
     // 2. An object of component options, such as { name: 'foo', render: [Function], props: {...} }
     // Depending what it is, we do different things.
-    if (type === Transition || type === TransitionGroup) {
+    if (type === Transition && stubs['transition']) {
+      return [createTransitionStub({ props: undefined }), undefined, children]
+    }
+
+    if (type === TransitionGroup && stubs['transition-group']) {
       return [createTransitionStub({ props: undefined }), undefined, children]
     }