VueJS

Vue the Mirage from this angle!

Published Jan 6, 2020

Updated May 30, 2023

13 min read

Fire the base of Vue.js! - 2 Part Series

This article was written over 18 months ago and may contain information that is out of date. Some content may be relevant but please refer to the relevant official documentation or available resources for the latest information.

Despite being designed in the late 1970’s, the lightweight Mirage jet fighter is the topic of today’s article!

You might assume that I’m kidding, but I’m not!

We are going to look at Mirage from a different angle in this article. The Vue.js angle!

In the early stages of full-stack app development, everything is subject to change. The database structure is not complete, Web APIs are still under construction, and the front-end development is on-going. Building the layout, and writing all HTML/CSS can be a much faster process when you have a specific design in mind.

At some point, it's not unusual for the front-end developers to be stalled or blocked by the incomplete back-end APIs. They need to populate some dynamic sections based on data eventually coming through from the backend.

Solutions for this problem, which I’ve employed in the past, include using mock files or in-memory databases to see how things will pan out. The down side? It does come with its hiccups.

That’s why Mirage.js exists! Mirage.js is a client-side server that embeds itself into the app. It handles all of the API endpoints calls without the need for a real backend server.

This article will introduce to you Mirage.js as we'll build a Note Writer app in Vue.js.

The source code of this article can be cloned from this GitHub repo: Notes Writer.

How can Mirage.js help?

Developing an app with the backend API development lagging can bring things to a halt for the front-end team. That’s why we tend to use workarounds like reading from mock files, or even building fake in-memory services to simulate API responses. This enables us to build the front-end, display and render any dynamic data, and get a full picture of what the app looks like once it’s done.

For instance, each mock file mimics a separate database entity. You then add client-side Web services to read the mock files, and make their content available to the app. When the backend APIs are ready, you simply visit these services, and amend the code to interact with the real API endpoints instead. That’s easy, but time is wasted replacing the mock Web services with the real ones.

This approach creates extra work for the developer, and extensive time later coding the services to communicate with the real API endpoints.

Mirage.js offers a simple solution for this: an approach that requires no code changes at all when it’s time to use the real API endpoints.

With Mirage.js, you create an instance of a Server object. This object is the window through which Mirage.js interacts with your application and handles all API endpoints.

Routes and Route Handlers

Inside this Server object instance, you define a set of routes and route handlers. A route and a route handler look like this:

this.get("/notes", () => {
	return [
		{ id: "1", body: "The first note body goes here", title: "First Note" },
		{ id: "2", body: "The second note body goes here", title: "Second Note" },
		{ id: "3", body: "The third note body goes here", title: "Third Note" }
	];
})

For a moment, you feel you are writing some Node.js backend code!

This snippet defines a GET route having an endpoint of /notes. The second parameter of the get() route function defines the route handler, that is, the code that runs when the route /notes is called. The route handler returns notes data.

You can define more routes and route handlers as your app needs. For instance, you can define all CRUD routes including POSTING a new note, PATCHING an existing note, and DELETING an existing note.

Mirage.js supports all HTTP Verbs. In addition, to simulate a real API response delay, Mirage.js allows you to pass, as a third argument to the route function, a timing object that specifies the amount of delay in milliseconds to incur before returning a response to the client-side app. You can define this timing object as:

this.get("/notes", () => {
	return [
		{ id: "1", body: "The first note body goes here", title: "First Note" },
		{ id: "2", body: "The second note body goes here", title: "Second Note" },
		{ id: "3", body: "The third note body goes here", title: "Third Note" }
	];
}, { timing: 5000 })

Mirage.js Database and ORM

So far, we introduced the static route handlers. The route handler statically defines the set of data to return every time the route is requested.

What if you want the ability to add new notes? Delete existing? Edit existing? Then you can use the dynamic route handlers supported by Mirage.js.

In order to support dynamic data, Mirage.js offers an in-memory database that is accessed by the server.db object instance.

Along with the database support, Mirage.js comes with an ORM. You will spend most of your time working with the ORM instead of accessing the database directly. With the ORM, you can create, update, delete, and query for data inside the database.

For the ORM/Database integration to work, you should define your models inside the Server object. The models represent the entities you are dealing with within your application. Also, models are registered by the ORM that use them to shape the data returned from the database.

To define a model in your Server object, you:

import { Server, Model } from "miragejs";

new Server({
	models: {	
		note: Model
	},

	routes () {
		this.namespace = "api";

		this.get("/notes", schema => {
			return schema.notes.all();
		})
	}
});

You wrap all your models inside the models object. Any model you define is of type Model class.

Internally, Mirage.js stores a collection of notes. By default, it pluralizes the model name you have given. Now you can add/edit/remove notes from this collection.

Then, you refactor the route handler to make use of the schema object. The schema object is provided as the first parameter on the route handler. It represents the ORM gateway to access all the collections stored inside the database.

The schema object adds functionality to the collections. For example, it adds a set of functions that are essential to retrieve, edit, create, and delete data from the collections.

schema.notes.create();
schema.notes.all();
schema.notes.find();
schema.notes.findBy();
schema.notes.where();
schema.notes.destory();

By using the ORM API, you let Mirage.js shape and use internal serializers to format your data as JSON, or any other supported format, and make your data ready to be transmitted to the front-end app.

A second parameter that a route handler accepts is the request parameter. The request parameter represents the current HTTP Request object.

To complete this section, it’s worth mentioning the seeds() function that you can use to seed your database with some initial data:

import { Server, Model } from "miragejs";

new Server({
	models: {	
		note: Model
	},

	routes () {
		this.namespace = "api";

		this.get("/notes", schema => {
			return schema.notes.all();
		})
	},

	seeds (server) {
		server.create("note", { body: "# An h1 header", title: "# An h1 header" });
		server.create("note", { body: "## An h2 header", title: "## An h2 header" });
		server.create("note", { body: "### An h3 header", title: "### An h3 header" });
		server.create("note", { body: "#### An h4 header", title: "#### An h4 header" });
		server.create("note", { body: "##### An h5 header", title: "##### An h5 header" });
		server.create("note", { body: "###### An h6 header", title: "###### An h6 header" });
	}
});

The seeds() function accepts the server object as an input parameter. You make use of the server.create() function to seed initial data in the database.

One important aspect of Mirage.js is that it auto-generates values for the id field for each and every record in the notes collection.

The Mirage.js team has done a great job of documenting this product. You can consult the documentation website to read more about Mirage.js.

Demo

Now that we've laid down the basics of Mirage.js, let’s start using it to build a Vue.js Notes Writer app.

Create a new Vue.js app

To start, make sure you install the latest version of the Vue CLI by running this command:

npm install -g @vue/cli

The command downloads and installs the latest bits of the Vue CLI on your computer.

To verify the version of the Vue CLI installed, you can run this command:

vue --version

The command displays:

@vue/cli 4.1.1

To create a new Vue.js app, run the following command:

vue create notes-writer-app

This command triggers a set of questions to shape the features to be included in the new app. You are free to choose the options that suit your app. In my case, I’ve chosen the following:

Vue CLI v4.1.1
? Please pick a preset:
  default (babel, eslint)
❯ Manually select features

? Check the features needed for your project:
 ◉ Babel
 ◯ TypeScript
 ◯ Progressive Web App (PWA) Support
 ◯ Router
 ◉ Vuex
 ◉ CSS Pre-processors
 ◉ Linter / Formatter
❯◯ Unit Testing
 ◯ E2E Testing

? Pick a CSS pre-processor (PostCSS, Autoprefixer and CSS Modules are supported by default)
:
  Sass/SCSS (with dart-sass)
❯ Sass/SCSS (with node-sass)
  Less
  Stylus

? Pick a linter / formatter config:
  ESLint with error prevention only
  ESLint + Airbnb config
❯ ESLint + Standard config
  ESLint + Prettier

? Pick additional lint features:
❯◯ Lint on save
 ◉ Lint and fix on commit

? Where do you prefer placing config for Babel, ESLint, etc.?
  In dedicated config files
❯ In package.json

The CLI takes a few seconds to download and install all the bits. Once done, you can navigate to the newly created app folder and run the app:

cd notes-writer-app
npm run serve

Now that the Vue.js app is created, let’s install the required NPM packages for this app.

Install NPM dependencies

A few additional NPM packages are required by the Notes Writer app. To install them, follow the steps below:

npm install --save axios

This command installs the axios library to allow us to communicate with a backend API using HTTP Requests.

npm install --save lodash

This command installs the lodash library. This library gives us a handful set of JavaScript functions to perform complex tasks.

npm install --save marked

The command above installs the marked library. This library is used to convert Markdown text into HTML content. The Notes Writer app allows the user to write his/her notes using Markdown text. With the help of this library, the app shows the converted content in HTML right away.

npm install --save miragejs

The command above installs the miragejs library. This library will be used to build a client-side server to handle backend API requests.

One more dev-dependency is required since we will be using SASS is the sass library itself. You can install it by running:

npm install --save-dev sass

Those are all the NPM packages we need.

Let’s move on and introduce the Notes Writer app.

Introduce the UI

Before we start building the Notes Writer app, let me share the final app, and what it looks like when running it in a browser:

The app is split into two main sections:

Notes List: This section lists all the saved notes in the app.
Notes Editor: This section provides an editor to input the note content (Markdown or normal text). In addition, it displays a live preview of whatever text is typed inside the editor.

When the user starts typing, the Save and Clear buttons appear. The Save button is used to save the new or existing notes, while the Clear button clears the editor and disregards any text inside the editor.

The user can click a saved note in order to edit its content. When an existing note is being edited, an additional button named Delete appears to allow the user to delete an existing note.

Let’s start building this app!

Build the UI

Let’s start by building the Notes component. The template of this component is as follows:

<template>
  <div class="notes-container">
    <NotesList
      :notes="notes"
      @set-note="setNote"
      class="notes-container__list"
    ></NotesList>
    <NotesCreate
      :note="currentNote"
      @save-note="saveNote"
      @set-note="setNote"
      @delete-note="deleteNote"
      class="notes-container__create"
    ></NotesCreate>
  </div>
</template>

The template above embeds two other components:

NotesList component. This component receives a collection of note records as input.
NotesCreate component. This component receives the currently active note (being edited or viewed) as input.

The NotesList component exposes an event set-note that is emitted when the user clicks on an existing note to read or edit.

The NotesCreate component exposes a set of events:

save-note, emitted when the user clicks on the Save button to save a note.
set-note, emitted when the user starts typing a new note. The app employs a mechanism that keeps track of what the user is typing, and emits the set-note event. This event is handled by the Vuex Store to save the contents of the current note in a temporary placeholder inside the Store. In addition, this event is emitted when the user clicks on the Clear button to clear the editor.
delete-note emitted when the user clicks on the Delete button to delete an existing note.

The Notes component handles all the events emitted by its children components, and redirects them to the Vuex Store, where they are handled in one centralized place.

This component and the rest of the components use scoped SCSS in their templates:

<style lang="scss" scoped>
	@import "@/styles/components/notes.scss";
</style>

I’ve placed all the SCSS files inside a single /src/styles folder with the following structure:

components folder holding all the SCSS files for all components.
_variables.scss file to hold all SCSS variables used in the app
global.scss file to hold a reference to the _variables.scss file or any other SCSS that needs to be shared among the components style sheet files.

You may add additional subfolders in your apps depending on the need and scenario at hand.

In order to make the global.scss available to all the components in the app you need to create a new file (or modify the exising one) at the root of the project folder named vue.config.js and paste the following content inside it:

// vue.config.js
module.exports = {
  css: {
    loaderOptions: {
      sass: {
        prependData: `@import "@/styles/global.scss";`
      }
    }
  }
}

The global.scss file will be prepended to any other SCSS files in the app and will be available everywhere.

The NotesList component template is as follows:

<template>
  <div class="notes">
    <div class="notes__items">
      <Note
        v-for="(note, index) in notes"
        :key="index"
        v-bind="note"
        class="notes__items__item"
        @set-note="setNote(note)"
      ></Note>
    </div>
  </div>
</template>

This component iterates over the collection of note records and renders each note inside its own NoteItem component. As well, it handles the set-note event that is triggered by the NoteItem component.

The NoteItem component template is as follows:

<template>
  <div
    class="notes__item"
    @click.prevent="setNote"
  >
    <h4>{{ title }}</h4>
    <p class="notes__item__body">{{ body }}</p>
  </div>
</template>

The component displays the Note title and body.

The NotesCreate component template is as follows:

<template>
  <div class="editor__md">
    <div class="editor">
      <div v-if="showControls">
        <button
          class="btn btn-new-note"
          @click="saveNewNote"
        >Save</button>
        <button
          class="btn btn-clear-note"
          @click="resetNote"
        >Clear</button>
        <button
          class="btn btn-delete-note"
          v-if="showDeleteBtn"
          @click="deleteNote"
        >Delete</button>
      </div>
      <textarea
        name="markdown"
        :value="currentNote"
        @input="onNoteChanged"
        placeholder="Type your note here ..."
      ></textarea>
    </div>
    <div class="editor__compiled-md">
      <div v-html="compiledMarkdown"></div>
    </div>
  </div>
</template>

This template is a bit more involved. It starts by displaying the Control Buttons. Then it displays the textarea that’s used as an editor. Finally, it displays the compiled Markdown to the right side of the editor.

The Control buttons are shown based on the showControls computed property that’s defined as follows:

currentNote () {
	return this.note && this.note.body
},
showControls () {
  return !!this.currentNote
},

If there is a current note (whether a new one or an existing one selected) to show the Controls buttons.

As for the Delete button, it’s visibility is controlled by the showDeleteBtn button defined as follows:

showDeleteBtn () {
	return !!this.note.id
},

Show the Delete button only when an existing note is being edited.

The rest of the UI files in the app are related to styling that you can check and go through by visiting the GitHub repo of this app.

Build the Server with Mirage.js

Open the main.js file, and add the following just before the instantiation of the main Vue instance:

import { Server, Model } from 'miragejs'

/* eslint-disable no-new */
new Server({
	models: {
		note: Model
	},

	routes () {
		this.namespace = 'api'

		this.get('/notes', schema => {
		  return schema.notes.all()
		})

		this.post('/notes', (schema, request) => {
		  let attrs = JSON.parse(request.requestBody)
		  let newNote = schema.notes.create(attrs)
		  return schema.notes.find(newNote.id)
		})

		this.patch('/notes/:id', (schema, request) => {
		  let newAttrs = JSON.parse(request.requestBody)
		  let id = request.params.id
		  let note = schema.notes.find(id)

		  return note.update(newAttrs)
		})

		this.delete('/notes/:id', (schema, request) => {
		  let id = request.params.id
		  return schema.notes.find(id).destroy()
		})
	},

	seeds (server) {
		server.create('note', { body: '# An h1 header', title: '# An h1 header' })
		server.create('note', { body: '## An h2 header', title: '## An h2 header' })
		server.create('note', { body: '### An h3 header', title: '### An h3 header' })
		server.create('note', { body: '#### An h4 header', title: '#### An h4 header' })
		server.create('note', { body: '##### An h5 header', title: '##### An h5 header' })
		server.create('note', { body: '###### An h6 header', title: '###### An h6 header' })
	}
});

The server instance defines the CRUD routes and route handlers. For instance, the post() route handler parses the request.requestBody to access the payload of this post request. It then uses the ORM schema object to create a new note record. Finally, it uses the ORM schema object to find the newly created note, and returns it to the front-end app.

The server makes use of the seeds() function to initialize the database with some preliminary set of note records.

The routes() function sets the namespace to a value of api. Consequently, this means that any route URL will be suffixed with the /api URL segment. To get all notes stored in the database, you issue a GET request to /api/notes.

Now that the Mirage.js backend server is ready, let’s move on and build the Vuex Store.

Build the Vuex Store

The Store defines the following state:

state: {
	notesList: [],
	note: {}
},

It defines the notesList array to hold the list of all notes in the app, and defines the note object to hold the currently selected or newly created note.

The Store defines a set of actions:

async getNotesList ({ commit }) {
  let notes = [];

	await axios.get('/api/notes')
	.then(response => {
		notes = response.data.notes
	});

	commit('setNotesList', notes)
},

This action issues a GET request to /api/notes to retrieve all notes stored in the database. It then commits the notes into the store by calling the setNotesList mutation.

The setNotesList mutation is defined as follows:

setNotesList (state, notes) {
	state.notesList = notes
},

Another important action is the setNote action defined as:

setNote ({ commit }, { id = '', body = '' } = {}) {
	commit('setNote', { id, body })
},

This action is triggered when the user selects an existing note. Also, it is being triggered while the user is editing an existing note or creating a new note. It receives, as input, the id and body of the note. It commits the data into the store by calling the setNote mutation.

The setNote mutation is defined as:

setNote (state, { id, body }) {
	let note = {}

	if (id) {
		note = state.notesList.find(note => note.id === id)
		const newNoteBody = body || note.body

		note = { ...note, body: newNoteBody, title: newNoteBody.substring(0, 20) }
	} else if (body) {	
		note = { body, title: body.substring(0, 20) }
	}

	state.note = note
},

If the id input parameter is valid, it retrieves the existing note from the state.notesList array, and updates the content of the existing note. Otherwise, this is a new note. The code checks if the user has typed any content. If it does, it creates a new note record.

Finally, it sets the state.note to either the existing note or to the newly created note. This also covers the case in which the user clears the content of the editor, and resets the state.note object.

Another action that’s defined by the Store is the deleteNote action, which is defined as:

async deleteNote ({ commit, state }) {
	let id = (state.note && state.note.id)

	if (id) {
		let url = `/api/notes/${state.note.id}`
		await axios.delete(url)
	}

	commit('deleteNote', { id })
},

The action retrieves the note ID of the note currently stored inside the state.note object. If one exists, this means that there is an existing note that’s being edited right now. It then issues a DELETE Http Request to remove this note. Finally, it commits the results into the Store by calling the deleteNote mutation.

The deleteNote mutation is defined as follows:

deleteNote (state, { id }) {
	if (id) {
		state.notesList = state.notesList.filter(n => n.id !== id)
	}

	state.note = null
},

The deleteNote mutation filters out the deleted note from the state.notesList, and resets the existing state.note object.

The last action defined by the Store is the saveNote action that’s defined as:

async saveNote ({ commit, state }) {
	let note = {}

	let url = state.note.id ? `/api/notes/${state.note.id}` : '/api/notes'
	let method = state.note.id ? 'patch' : 'post'

	await axios({
		method,
		url,
		data: state.note
	}).then(response => {
		note = response.data.note
	})

	commit('saveNote', note)
}

This action checks if the currently edited note is an existing note or a new one. Accordingly, it sends a POST or PATCH request to the backend server to either create the new note or update an existing one. Finally, it commits the results into the Store by calling the saveNote mutation.

The saveNote mutation is defined as follows:

saveNote (state, note) {
	const notePosition = state.notesList.findIndex(n => n.id === note.id)

	if (notePosition < 0) {
		state.notesList.push(note)
	} else {
		state.notesList.splice(notePosition, 1, note)
	}

	state.note = null
}

The mutation above adds, or amends, a note inside the state.notesList to properly sync with the backend database.

Finally, the Store defines two getters to allow components to retrieve data from the state as:

getters: {
	notes: state => state.notesList,
	currentNote: state => state.note
},

That’s all that we have for the Store for the time being. Let’s see how the components make use of this Store in the next section.

Integrate the Store in the app

The components NoteItem, NotesList, and NotesCreate communicate with the Notes component via the this.$emit() event bus. And in turn, the Notes component communicates with the Store via Getters and Actions.

The Notes component defines the following code:

computed: {
	...mapGetters(['notes', 'currentNote'])
},
mounted () {
	this.getNotesList()
},
methods: {
	...mapActions(['getNotesList', 'saveNote', 'setNote', 'deleteNote'])
}

Inside the computed property, it imports the notes and currentNote Store getters. These getters are now available as computed properties inside this component. Inside the methods section, it imports the Store actions: getNotesList, saveNote, setNote, and deleteNote. These actions become methods defined in this component, and can be called like any other method defined.

The mounted lifecycle hook calls the getNotesList() action to retrieve the list of notes from the backend API, and fill the Store with the data.

<NotesCreate
	:note="currentNote"
	@save-note="saveNote"
	@set-note="setNote"
	@delete-note="deleteNote"
	class="notes-container__create"
></NotesCreate>

Notice how the events emitted by the NotesCreate component are bound directly to the methods (actions mapped to method names inside the component). When the user clicks the Save button, the action method saveNote is triggered automatically inside the Store.

The same applies to the rest of the actions in this component.

Run the app

Run the following command and start playing around with the app:

npm run serve

The app runs on the port 8080, and can be accessed by visiting the following URL: http://localhost:8080.

Start typing text inside the editor. You can use Markdown text. Notice how the compiled Markdown text is displayed on the right side of the editor. You may click the Save button to create a new note, or clear the editor. You can also click an existing note to load its content inside the editor.

Conclusion

This article demonstrates how you can continue working on the front-end side of your application while the backend is being built, especially during the early stages of development.

In future installments, I will be showing you how to integrate this app with Google Firebase to store the data, and authenticate users. You will be able to login to the app and manage your own set of notes.

This Dot is a consultancy dedicated to guiding companies through their modernization and digital transformation journeys. Specializing in replatforming, modernizing, and launching new initiatives, we stand out by taking true ownership of your engineering projects.

We love helping teams with projects that have missed their deadlines or helping keep your strategic digital initiatives on course. Check out our case studies and our clients that trust us with their engineering.

About the author(s)

Bilal Haidar
Author, Developer, and Mentor: Professional ASP.NET 3.5 Security, Membership, and Role Management with C# and VB | A Complete Guide to VueJS
@bhaidar @bhaidar

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Understanding Vue.js's <Suspense> and Async Components

In this blog post, we will delve into how and async components work, their benefits, and practical implementation strategies to make your Vue.js applications more efficient and user-friendly. Without further ado, let’s get started! Suspense Let's kick off by explaining what Suspense components are. They are a new component that helps manage how your application handles components that need to await for some async resource to resolve, like fetching data from a server, waiting for images to load, or any other task that might take some time to complete before they can be properly rendered. Imagine you're building a web page that needs to load data from a server, and you have 2 components that fetch the data you need as they will show different things. Typically, you might see a loading spinner or a skeleton while the data is being fetched. Suspense components make it easier to handle these scenarios. Instead of manually managing loading states and error messages for each component that needs to fetch data, Suspense components let you wrap all these components together. Inside this wrapper, you can define: 1. What to show while the data is loading (like a loading spinner). 2. The actual content that should be displayed once the data is successfully fetched. This way, Vue Suspense simplifies the process of handling asynchronous operations (like data fetching) and improves the user (and the developer) experience by providing a more seamless and integrated way to show loading states and handle errors. There are two types of async dependencies that can wait on: - Components with an async setup() hook. This includes components using with top-level await expressions. *Note: These can only be used within a component.* - Async Components. Async components Vue's asynchronous components are like a smart loading system for your web app. Imagine your app as a big puzzle. Normally, you'd put together all the pieces at once, which can take time. But what if some pieces aren't needed right away? Asynchronous components help with this. Here's how they work: - Load Only What's Needed: Just like only picking up puzzle pieces you need right now, asynchronous components let your app load only the parts that are immediately necessary. Other parts can be loaded later, as needed. - Faster Start: Your app starts up faster because it doesn't have to load everything at once. It's like quickly starting with the border of a puzzle and filling in the rest later. - Save Resources: It uses your web resources (like internet data) more wisely, only grabbing what’s essential when it's essential. In short, asynchronous components make your app quicker to start and more efficient, improving the overall experience for your users. Example: ` Combining Async Components and Suspense Let's explore how combining asynchronous components with Vue's Suspense feature can enhance your application. When asynchronous components are used with Vue's Suspense, they form a powerful combination. The key point is that async components are "suspensable" by default. This means they can be easily integrated with Suspense to improve how your app handles loading and rendering components. When used together, you can do the following things: - Centralized Loading and Error Handling: With Suspense, you don't have to handle loading and error states individually for each async component. Instead, you can define a single loading indicator or error message within the Suspense component. This unified approach simplifies your code and ensures consistency across different parts of your app. - Flexible and Clean Code Structure: By combining async components with Suspense, your code becomes more organized and easier to maintain. An asynchronous component has the flexibility to operate independently of Suspense's oversight. By setting suspensible: false in its options, the component takes charge of its own loading behavior. This means that instead of relying on Suspense to manage when it appears, the component itself dictates its loading state and presentation. This option is particularly useful for components that have specific loading logic or visuals they need to maintain, separate from the broader Suspense-driven loading strategy in the application. In practice, this combo allows you to create a user interface that feels responsive and cohesive. Users see a well-timed loading indicator while the necessary components are being fetched, and if something goes wrong, a single, well-crafted error message is displayed. It's like ensuring that the entire puzzle is either revealed in its completed form or not at all rather than showing disjointed parts at different times. How it works When a component inside the boundary is waiting for something asynchronous, shows fallback content. This fallback content can be anything you choose, such as a loading spinner or a message indicating that data is being loaded. Example Usage Let’s use a simple example: In the visual example provided, imagine we have two Vue components: one showcasing a selected Pokémon, Eevee, and a carousel showcasing a variety of other Pokémon. Both components are designed to fetch data asynchronously. Without , while the data is being fetched, we would typically see two separate loading indicators: one for the Eevee Pokemon that is selected and another for the carousel. This can make the page look disjointed and be a less-than-ideal user experience. We could display a single, cohesive loading indicator by wrapping both components inside a boundary. This unified loading state would persist until all the data for both components—the single Pokémon display and the carousel—has been fetched and is ready to be rendered. Here's how you might structure the code for such a scenario: ` Here, is the component that's performing asynchronous operations. While loading, the text 'Loading...' is displayed to the user. Great! But what about when things don't go as planned and an error occurs? Currently, Vue's doesn't directly handle errors within its boundary. However, there's a neat workaround. You can use the onErrorCaptured() hook in the parent component of to catch and manage errors. Here's how it works: ` If we run this code, and let’s say that we had an error selecting our Pokemon, this is how it is going to display to the user: The error message is specifically tied to the component where the issue occurred, ensuring that it's the only part of your application that shows an error notification. Meanwhile, the rest of your components will continue to operate and display as intended, maintaining the overall user experience without widespread disruption. This targeted error handling keeps the application's functionality intact while indicating where the problem lies. Conclusion stands out as a formidable feature in Vue.js, transforming the management of asynchronous operations into a more streamlined and user-centric process. It not only elevates the user experience by ensuring smoother interactions during data loading phases but also enhances code maintainability and application performance. I hope you found this blog post enlightening and that it adds value to your Vue.js projects. As always, happy coding and continue to explore the vast possibilities Vue.js offers to make your applications more efficient and engaging!...

Apr 24, 2024

6 mins

VueWeb PerformanceUXJavaScript

Introducing the release of Vue 3

Back in October 2018, Evan You announced plans to start building the third version of VueJS. Featuring 30+ RFCs, over 2,600 commits, 628 pull request from 99 contributors, Vue 3's release reflects tireless ingenuity, passion, and hard work. Its release, no doubt, is a cause for celebration for all of the Vue community members who have been eagerly awaiting it. I, for one, am thrilled to share some resources that I believe will help developers migrate to Vue 3: - Vue 2 -> Vue 3 Migration Guide - Vue Router 3.0 -> Vue Router 4.0 Migration Guide - Vuex 4 - Chrome Vue JS DevTools - FireFox DevTools Here at This Dot, we have tracked Vue 3's development from the onset. We have written blog posts, published a book, hosted Vue Meetups, debuted JavaScript Marathon, shared Modern Web Podcasts, and more! Today, we’ll take a guided tour through all the material we have shared on Vue 2 and Vue 3. Blog Posts Here are our latest blog posts on Vue 3: - How to Set Up Storybook in Vue 3 - Async Components in Vue 3 - Your first Vue 3 app using TypeScript - Teleporting in Vue 3 - Content Distribution in Vue 3 - Custom Directives in Vue 3 - Vue 3 Composition API, do you really need it? You may access the remaining blog posts at This Dot Labs Blog. A Complete Guide to VueJS In April 2020, This Dot released A Complete Guide to VueJS by Bilal Haidar. This book is a precise, and detailed resource for learning VueJS, and highlights some top courses for Vue and JavaScript. Most importantly, it gives a brief introduction to almost all the new features in Vue 3. Grab your own copy for free! Vue Meetups We have hosted more than 10+ Vue Meetups in the past year with dozens of speakers, including Evan You, other Vue Core team members, and Vue developers interested in the future of the framework. To watch past meetup recordings, follow this link to get access to all the meetups on one page. JavaScript Marathon This Dot's team delivered six free live Vue JS tutorials during the JavaScript Marathon. Here’s a list of all the VueJS live sessions recordings: - 1 Hour to Learn Vue - Master State Management in Vue with VueX - Master PWA in Vue - Learning Unit Testing in Vue - Pro Tips on Using AWS with Vue - Debugging Vue: Quick Tips and Tricks Modern Web Podcasts This Dot's team delivered more than 40+ podcasts in the last two years. Here’s a link to the Vue JS Podcasts: - S07E1 Modern Web Podcast - Introducing Vite - Evan You’s new project + Vue 3 Updates - S06E12 Modern Web Podcast - Vue 3, Code Education, & the Vue Community - S06E4 Modern Web Podcast - Vue Updates with Chris Fitz, Jake Dohm, and Rob Ocel The Future of Vue The team at This Dot is hardly finished tracking Vue's progress, as well as the progress of many other web based technologies. To join us on our technical exploration journey, be sure to follow This Dot Media on Twitter! If you have specific questions about how to begin your Vue 3 migration, or have general questions about Vue 3, don't hesitate to reach out to us at hi@thisdot.co....

Sep 18, 2020

4 mins

VueJavaScriptWeb Development

Understanding the Difference Between `:focus` and `:focus-visible` in CSS

Understanding the Difference Between :focus and :focus-visible in CSS I have learned my fair share about the importance of keyboard accessibility, so I know that visual indication of the focused element is very important. But the well-known :focus pseudo-class is not always the best fit for this job. That's where :focus-visible comes in. Let's look at the differences between these two pseudo-classes and explore the best practices for using them effectively. What is the :focus Pseudo-Class? The :focus pseudo-class is a CSS selector that applies styles to any element that receives focus, regardless of how that focus was triggered. This includes focus events from keyboard navigation, mouse clicks, and touch interactions. Example Usage of :focus ` In this example, the button will display a blue outline whenever it is focused, whether the user clicks on it with a mouse, taps it on a touchscreen, or navigates to it using the keyboard. What is the :focus-visible Pseudo-Class? The :focus-visible pseudo-class is more specialized. It only applies styles to an element when the browser determines that the focus should be visible. This typically occurs when the user navigates via the keyboard or assistive technologies rather than through mouse or touch input. Example Usage of :focus-visible ` Here, the button will only show a blue outline when focused through keyboard navigation or another input method that usually requires visible focus indicators. Key Differences Between :focus and :focus-visible :focus - Behavior: Applies to any element that receives focus, regardless of the input method. - Use Cases: Ensures that all interactions with the element are visually indicated, whether by mouse, keyboard, or touch. :focus-visible - Behavior: Applies styles only when the focus should be visible, such as using a keyboard or assistive technology. - Use Cases: Ideal for scenarios where you want to provide focus indicators only to keyboard and assistive technology users while avoiding unnecessary outlines for mouse and touch users, typically required by design. Accessibility Implications :focus - Pros: - Guarantees that all users can see when an element is focused, which is critical for accessibility. - Cons: - Can lead to a suboptimal experience for mouse users, as focus styles may appear unnecessarily during mouse interactions. :focus-visible - Pros: - Enhances user experience by showing focus indicators only when necessary, thus keeping the interface clean for mouse and touch users. - Tailors the experience for keyboard and assistive technology users, providing them with clear visual cues. - Cons: - Additional considerations may be required to ensure that focus indicators are not accidentally omitted, especially in older browsers that do not support :focus-visible. - There may be cases where you want to show focus indicators for all users, regardless of input method. Best Practices for Using :focus and :focus-visible To achieve the best accessibility and user experience, combining both :focus and :focus-visible in your CSS is often a good idea. Combining :focus and :focus-visible ` Here is a Stackblitz example of what such styling could look like for you to try out and play with. Additional Tips - Test with Keyboard and Assistive Technology: Ensure that your web application is navigable using a keyboard (Tab, Shift + Tab, etc.) and that focus indicators are visible for those who rely on them. It's never a bad idea to include accessibility testing in your e2e testing suite. - Provide Clear Focus Indicators: Make sure that focus indicators are prominent and easy to see. A subtle or hard-to-spot focus indicator can severely impact accessibility for users who rely on keyboard navigation. Conclusion The :focus-visible pseudo-class offers a more refined way to manage focus indicators, improving accessibility and user experience, particularly for keyboard and assistive technology users. By understanding the differences between :focus and :focus-visible, and applying best practices in your CSS, you can create more accessible and user-friendly web applications. Remember, accessibility should never be an afterthought. By thoughtfully applying focus styles, you ensure that all users, regardless of how they interact with your site, can easily navigate and interact....

Nov 8, 2024

3 mins

AccessibilityCSSPlaywright

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