Add petite-vue plugins support

Author: ws-rush

README.md

@@ -306,6 +306,35 @@ createApp({
 }).mount()
 ```
 
+### Use Plugins
+
+You can write custome directive then distrbute it as a pacage, then add it to create vue, like:
+
+```html
+<div v-scope="{counter: 0}" v-log="inside petite-vue scope">
+  <button @click="counter++">increase</button>
+</div>
+
+<script type="module">
+  import log from './log'
+  import { createApp } from 'peteite-vue'
+  createApp().use(log).mount()
+</script>
+```
+
+A plugin code similar to vue plugins code:
+
+```js
+// inside log.js plugin file
+export default {
+  install: (app, options) => {
+    app.directive('log', ({exp}) => {
+      console.log(exp)
+    })
+  }
+}
+```
+
 ## Examples
 
 Check out the [examples directory](https://github.com/vuejs/petite-vue/tree/main/examples).

src/app.ts

@@ -42,6 +42,11 @@ export const createApp = (initialData?: any) => {
       }
     },
 
+    use(plugin: any, options = {}) {
+      plugin.install(this, options)
+      return this
+    },
+
     mount(el?: string | Element | null) {
       if (typeof el === 'string') {
         el = document.querySelector(el)