Vue Tutorial: An Overview and Walkthrough

We’re in a golden era of JavaScript libraries and frameworks. More and more companies are building out full, dynamic web apps in addition to - or in lieu of - traditional desktop applications. This means things are constantly changing and frameworks are going in and out of vogue, but the core concepts of what we’re trying to accomplish remain similar.

Previously, I wrote a Getting Started with React guide that helped out a lot of beginner and intermediate developers. Vue.js is going toe-to-toe with React for popularity among JavaScript developers, so I’d like to offer the same straightforward and concise introduction for those who’d like to learn Vue as well. Let’s get started!

Prerequisites

Goals

We’re going to create a small application with Vue. The app will be a simple employee database and we’ll learn:

  • How to set up Vue
  • The anatomy of a Vue file
  • How to work with data, methods, conditional statements, and events in Vue
  • How to create, update, view, and delete users (employees) from the system
  • How to make API calls for each of the above actions
  • How to use tables, forms, and form validation
  • How to host a Vue build on GitHub pages

I’ve created a live demo and put the source up on GitHub.

(You can also view the demo on CodeSandbox.)

What is Vue?

  • Vue (or Vue.js) is an open-source front-end JavaScript framework
  • Vue is the view layer of an MVC application (Model View Controller)
  • Vue is currently one of the most popular JavaScript libraries/frameworks
  • Unlike other popular JavaScript projects, Vue is not backed by a large corporation like React (Facebook) or Angular (Google). Vue was originally written by Evan You and the open-source community.

Setup and Installation

There are two main ways to set up Vue - in a Node project, or directly injected into a static HTML file. I’d first like to take a look at setting up Vue in an HTML file, as it’s the simplest setup and introduction. Those who have only ever used a library like jQuery will be most familiar with this method. If you’ve already used React or another JavaScript framework, feel free to skip to the next section.

We can just create a basic HTML file and add a link to a Vue CDN in the head, and create a <div> with an id of app.

Static HTML File

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width,initial-scale=1.0" />
    <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>

    <title>Vue App</title>
  </head>

  <body>
    <div id="app"></div>
  </body>
</html>

We can create a simple “Hello World” with Vue. Using double brackets, we’ll render message in app. In the <script> tag, we’ll link the data and the DOM. We create a new Vue, and the message property on data will be rendered.

index.html

<html lang="en">
  <head>
    <meta charset="utf-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width,initial-scale=1.0" />
    <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>

    <title>Vue App</title>
  </head>

  <body>
    <div id="app">{{message}}</div>

    <script>
      const App = new Vue({
        el: '#app',
        data: {
          message: 'Hello Vue!',
        },
      })
    </script>
  </body>
</html>

We can see the data render.

vue1

At this point, it’s not very impressive, and it’s what you’ll learn in the introduction of the documentation, but it drives home the important point that Vue is just JavaScript, and there’s no need to get nervous about Node, Babel, Webpack, and so on.

#javascript #vue #tutorial #programming

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Vue Tutorial: An Overview and Walkthrough
Luna  Mosciski

Luna Mosciski

1600583123

8 Popular Websites That Use The Vue.JS Framework

In this article, we are going to list out the most popular websites using Vue JS as their frontend framework.

Vue JS is one of those elite progressive JavaScript frameworks that has huge demand in the web development industry. Many popular websites are developed using Vue in their frontend development because of its imperative features.

This framework was created by Evan You and still it is maintained by his private team members. Vue is of course an open-source framework which is based on MVVM concept (Model-view view-Model) and used extensively in building sublime user-interfaces and also considered a prime choice for developing single-page heavy applications.

Released in February 2014, Vue JS has gained 64,828 stars on Github, making it very popular in recent times.

Evan used Angular JS on many operations while working for Google and integrated many features in Vue to cover the flaws of Angular.

“I figured, what if I could just extract the part that I really liked about Angular and build something really lightweight." - Evan You

#vuejs #vue #vue-with-laravel #vue-top-story #vue-3 #build-vue-frontend #vue-in-laravel #vue.js

Teresa  Bosco

Teresa Bosco

1598685221

Vue File Upload Using vue-dropzone Tutorial

In this tutorial, I will show you how to upload a file in Vue using vue-dropzone library. For this example, I am using Vue.js 3.0. First, we will install the Vue.js using Vue CLI, and then we install the vue-dropzone library. Then configure it, and we are ready to accept the file. DropzoneJS is an open source library that provides drag and drops file uploads with image previews. DropzoneJS is lightweight doesn’t depend on any other library (like jQuery) and is  highly customizable. The  vue-dropzone is a vue component implemented on top of Dropzone.js. Let us start Vue File Upload Using vue-dropzone Tutorial.

Dropzone.js is an open-source library providing drag-and-drop file uploads with image previews. DropzoneJS is lightweight, doesn’t depend on any other library (like jQuery), and is highly customizable.

The vue-dropzone is a vue component implemented on top of Dropzone.js.

First, install the Vue using Vue CLI.

Step 1: Install Vue.js using Vue CLI.

Go to your terminal and hit the following command.

npm install -g @vue/cli
         or
yarn global add @vue/cli

If you face any error, try running the command as an administrator.

Now, we need to generate the necessary scaffold. So type the following command.

vue create vuedropzone

It will install the scaffold.

Open the project in your favorite editor. Mine is Visual Studio Code.

cd vuedropzone
code .

Step 2: Install vue-dropzone.

I am using the Yarn package manager. So let’s install using Yarn. You can use NPM, also. It does not matter.

yarn add vue2-dropzone

or

npm install vue2-dropzone

Okay, now we need to add one css file with the above package. Now, vue cli uses css loader, so we can directly import in the src >>  main.js entry file.

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

Vue.config.productionTip = false

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

import 'vue2-dropzone/dist/vue2Dropzone.css'

If importing css is not working for you, then you need to install that CSS file manually.

Copy this vue2Dropzone.css file’s content.

Create one file inside the src  >>  assets folder, create one css file called vuedropzone.css and paste the content there.

Import this css file inside src  >>  App.vue file.

<style lang="css">
  @import './assets/vuedropzone.css';
</style>

Now, it should include in our application.

Step 3: Upload an Image.

Our primary boilerplate has one ready-made component called HelloWorld.vue inside src  >>  components folder. Now, create one more file called FileUpload.vue.

Add the following code to FileUpload.vue file.

// FileUpload.vue

<template>
  <div id="app">
    <vue-dropzone id="upload" :options="config"></vue-dropzone>
  </div>
</template>

<script>
import vueDropzone from "vue2-dropzone";

export default {
  data: () => ({
    config: {
      url: "https://appdividend.com"
    }
  }),
  components: {
    vueDropzone
  }
};
</script>

Here, our API endpoint is https://appdividend.com. It is the point where we will hit the POST route and store our image, but it is my blog’s homepage, so it will not work anyway. But let me import this file into App.vue component and see what happens.

// App.vue

<template>
  <div id="app">
    <FileUpload />
  </div>
</template>

<script>
import FileUpload from './components/FileUpload.vue'

export default {
  name: 'app',
  components: {
    FileUpload
  }
}
</script>

<style lang="css">
  @import './assets/vuedropzone.css';
</style>

Now, start the development server using the following command. It will open up URL: http://localhost:8080.

npm run serve

Now, after uploading the image, we can see that the image upload is failed due to the wrong POST request endpoint.

Step 4: Create Laravel API for the endpoint.

Install the Laravel.

After that, we configure the database in the .env file and use MySQL database.

We need to create one model and migration file to store the image. So let us install the following command inside the Laravel project.

php artisan make:model Image -m

It will create both the Image model and create_images_table.php migrations file.

Now, open the migrations file and add the schema to it.

// create_images_table.php

public function up()
    {
        Schema::create('images', function (Blueprint $table) {
            $table->increments('id');
            $table->string('image_name');
            $table->timestamps();
        });
    }

Now, migrate the database table using the following command.

php artisan migrate

It creates the table in the database.

Now, we need to add a laravel-cors package to prevent cross-site-allow-origin errors. Go to the Laravel root and enter the following command to install it.

composer require barryvdh/laravel-cors

Configure it in the config  >>  app.php file.

Barryvdh\Cors\ServiceProvider::class,

Add the middleware inside app >>  Http  >>  Kernel.php file.

// Kernel.php

protected $middleware = [
        \Illuminate\Foundation\Http\Middleware\CheckForMaintenanceMode::class,
        \Illuminate\Foundation\Http\Middleware\ValidatePostSize::class,
        \App\Http\Middleware\TrimStrings::class,
        \Illuminate\Foundation\Http\Middleware\ConvertEmptyStringsToNull::class,
        \App\Http\Middleware\TrustProxies::class,
        \Barryvdh\Cors\HandleCors::class,
];

Step 5: Define the API route and method to store the image.

First, create an ImageController.php file using the following command.

php artisan make:controller ImageController

Define the store method. Also, create one images folder inside the public directory because we will store an image inside it.

Right now, I have written the store function that handles one image at a time. So do not upload multiple photos at a time; otherwise, it will break.

// ImageController.php

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\Image;

class ImageController extends Controller
{
    public function store(Request $request)
    {
       if($request->file('file'))
       {
          $image = $request->file('file');
          $name = time().$image->getClientOriginalName();
          $image->move(public_path().'/images/', $name); 
        }

       $image= new Image();
       $image->image_name = $name;
       $image->save();

       return response()->json(['success' => 'You have successfully uploaded an image'], 200);
     }
}

Go to the routes   >>  api.php file and add the following route.

// api.php

Route::post('image', 'ImageController@store');

Step 6: Edit FileUpload.vue component.

We need to add the correct Post request API endpoint in FileUpload.vue component.

// FileUpload.vue

<template>
  <div id="app">
    <vue-dropzone id="drop1" :options="config" @vdropzone-complete="afterComplete"></vue-dropzone>
  </div>
</template>

<script>
import vueDropzone from "vue2-dropzone";

export default {
  data: () => ({
    config: {
      url: "http://localhost:8000/api/image",
      
    }
  }),
  components: {
    vueDropzone
  },
  methods: {
    afterComplete(file) {
      console.log(file);
    }
  }
};
</script>

Now, save the file and try to upload an image. If everything is okay, then you will be able to save the image on the Laravel web server as well as save the name in the database as well.

You can also verify on the server side by checking the database entry and the images folder in which we have saved the image.

Step 7: More vue-dropzone configuration.

The only required options are url, but there are many more you can use.

For example, let’s say you want:

  • A maximum of 4 files
  • 2 MB max file size
  • Sent in chunks of 500 bytes
  • Set a custom thumbnail size of 150px
  • Make the uploaded items cancelable and removable (by default, they’re not)
export default {
  data: () => ({
    dropOptions: {
      url: "https://httpbin.org/post",
      maxFilesize: 5, // MB
      maxFiles: 5,
      chunking: true,
      chunkSize: 400, // Bytes
      thumbnailWidth: 100, // px
      thumbnailHeight: 100,
      addRemoveLinks: true
    }
  })
  // ...
}

Happy Coding !!!

Originally published at https://appdividend.com 

#vue #vue-dropzone #vue.js #dropzone.js #dropzonejs #vue cli

Willie  Beier

Willie Beier

1596728880

Tutorial: Getting Started with R and RStudio

In this tutorial we’ll learn how to begin programming with R using RStudio. We’ll install R, and RStudio RStudio, an extremely popular development environment for R. We’ll learn the key RStudio features in order to start programming in R on our own.

If you already know how to use RStudio and want to learn some tips, tricks, and shortcuts, check out this Dataquest blog post.

Table of Contents

#data science tutorials #beginner #r tutorial #r tutorials #rstats #tutorial #tutorials

Jeromy  Lowe

Jeromy Lowe

1599097440

Data Visualization in R with ggplot2: A Beginner Tutorial

A famous general is thought to have said, “A good sketch is better than a long speech.” That advice may have come from the battlefield, but it’s applicable in lots of other areas — including data science. “Sketching” out our data by visualizing it using ggplot2 in R is more impactful than simply describing the trends we find.

This is why we visualize data. We visualize data because it’s easier to learn from something that we can see rather than read. And thankfully for data analysts and data scientists who use R, there’s a tidyverse package called ggplot2 that makes data visualization a snap!

In this blog post, we’ll learn how to take some data and produce a visualization using R. To work through it, it’s best if you already have an understanding of R programming syntax, but you don’t need to be an expert or have any prior experience working with ggplot2

#data science tutorials #beginner #ggplot2 #r #r tutorial #r tutorials #rstats #tutorial #tutorials