Consolidating components into a Vue.js plugin

At this point, we have a structured approach for creating new Vue.js components and consolidating them into a single module export. Awesome! Next, we’ll bundle the components into a plugin to be registered on a Vue instance.

Remember that the Vue CLI creates a main.js entry point file in the root of the /src directory during the project initialization. Usually, that’s used as the entry point for a new Vue application. We’ll modify this to create the plugin.

If you’re landing on this post without reading the series introduction, jump there first.

main.js entry point #

Starting off, let’s remove the generated code. We’ll replace with the differences below.

// main.js

- import Vue from 'vue'
- import App from './App.vue'

- Vue.config.productionTip = false

- new Vue({
-  render: h => h(App),
- }).$mount('#app')

+ import * as components from './components'
+
+ const ComponentLibrary = {
+  install(Vue, options = {}) {
+    // components
+    for (const componentName in components) {
+      const component = components[componentName]
+
+      Vue.component(component.name, component)
+    }
+  }
+ }
+
+ export default ComponentLibrary
+
+ if (typeof window !== 'undefined' && window.Vue) {
+  window.Vue.use(ComponentLibrary)
+ }

The file should look like:

// main.js

import * as components from './components'

const ComponentLibrary = {
  install(Vue, options = {}) {
    // components
    for (const componentName in components) {
      const component = components[componentName]

      Vue.component(component.name, component)
    }
  }
}

export default ComponentLibrary

if (typeof window !== 'undefined' && window.Vue) {
  window.Vue.use(ComponentLibrary)
}

Let’s step through this 👀.

• Import the components from src/components. This will grab the components from the exports in index.js. That’s the file that imports(collects) the components that we want to include in the library.

• Now, we’ll create the Vue plugin and expose an install method. According to the Vue plugin documentation:

A Vue.js plugin should expose an install method…The method will be called with the Vue constructor as the first argument, along with possible options

• In the install method, iterate through the imported components and assign each component to the const component. The componentName is used as a key get the component out of the components object.

• Register each component with Vue.component(). The component.name is the name attribute from the component and the component as the component. When the plugin is registered in a Vue project, our components will be globally available.

• Export the component library plugin as the default. This allows for importing into another file as import ComponentLibrary from ... syntax:

import Vue from 'vue'
import ComponentLibrary from './main.js'

Vue.use(ComponentLibrary)

...

• Lastly, auto-register the plugin in situations where a Vue instance exists in the window and a module system is not used. We’ll give this a test when we publish the library to a content delivery network (CDN) and include it on a page after the included Vue tag. This is covered in the Vue Getting Started Guide and is an option when adopting Vue into an existing application that may not use a build system.

Currently, the above set up does one thing - registering components. That’s all we need it to do now but there are different patterns for plugin creation and the library entry point, main.js, in this case.

A few examples include:

• Adding directives, filters, and mixins
• Adding instance properties with Vue.prototype
• Importing style dependencies
• Merge user-defined options into the plugin registration with options = {}

The outline prescribed in the Vue documentation for writing a plugin is:

// 1. add global method or property
Vue.myGlobalMethod = function () {
  // some logic ...
}

// 2. add a global asset
Vue.directive('my-directive', {
  bind (el, binding, vnode, oldVnode) {
    // some logic ...
  }
  ...
})

// 3. inject some component options
Vue.mixin({
  created: function () {
    // some logic ...
  }
  ...
})

// 4. add an instance method
Vue.prototype.$myMethod = function (methodOptions) {
  // some logic ...
}

Source: https://vuejs.org/v2/guide/plugins.html#Writing-a-Plugin

One last tip #

Also, always remember to populate a name attribute in your components if using the Vue.component and component.name approach above. The registration will throw an error if component.name doesn’t exist.

<template>
  <div>
    <slot></slot>
  </div>
</template>

<script>
  export default {
    name: 'name-of-your-component' // 👈
  }
</script>

<style></style>

Give your components a name ☝️

Next up, tightening the feedback loop plus a hint of amazing documentation with VuePress 🌋.