DEV Community: Gio

Creating React “Widgets” that can be embedded on any website, by anyone

Gio — Mon, 10 Aug 2020 16:01:30 +0000

A software widget is a relatively simple and easy-to-use software application or component made for one or more different software platforms.
read more

Some of examples of a widget are the related content widget by Taboola. Or the newsletter widget, by MailChimp. In this article, we'll teach you how to build a reddit widget.

Why would I do this?

One example is for versatility in a widget you're making. Either for a client or for the world. A widget should be embeddable in as many places as possible, regardlesss of the software. Whether that website is made using WebFlow, Wordpress, Shopify, Drupal, doesn't matter. Additionally, its common for a widget to exist multiple times on the same page. Let's imagine a widget where we display the last 5 posts of a given subreddit. I should be able to embed that widget multiple times, for multiple subreddits, on the same page.

Keep in mind, we aren't building this widget for React developers. If that were the case, we'd just build a React Component and publish it on npm. Instead, we're building a widget that can be used by anyone, even a non-coder, outside of React.

We'll go over exactly how to do this. We'll start off by teaching you how to initialize multiple versions of your React App on the same page. Then, we'll learn how to pass data down the DOM, into our React App. This will allow us to present each of those widgets in different ways, by setting some attributes. Attributes which your customers can easily configure, without knowing how to code.

To get started, let's initialize a typical react app, using create-react-app.

npx create-react-app reddit-widget

ReactDOM's Render Function

When you first initialize a React App using create-react-app, you'll notice React attaches itself to a single element.

ReactDOM.render(
  <React.StrictMode>
    <App />
  </React.StrictMode>,
  document.getElementById('root')
);

ReactDOM's render function primarily takes two arguments. The first is the React Component you'll be injecting into the DOM. The second is the actual DOM element you'll be injecting the React Component into.

In the case above, we're injecting our <App /> component (wrapped in React's Strict Mode), into the #root div container in the DOM. Which you can find by navigating to public/index.html.

<div id="root"></div>

Multiple Instanes of React

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Now, what happens if we want multiple instances of this React App? We know how ReactDOM's render function works. Instead of injecting our app into a single div in the DOM, let's inject it into multiple.

First, we'll update index.js to iterate over multiple divs. To do this, we'll use document.querySelectorAll and search for all divs with a reddit_widget class specified. Then, we'll inject our React App into each of them.

// Find all widget divs
const WidgetDivs = document.querySelectorAll('.reddit_widget')

// Inject our React App into each
WidgetDivs.forEach(Div => {
  ReactDOM.render(
    <React.StrictMode>
      <App />
    </React.StrictMode>,
    Div
  );
})

At this point, our React App will be blank. That's because we don't have any divs with the reddit_widget class yet. Let's update our public/index.html file.

    <div class="reddit_widget"></div>
    <div class="reddit_widget"></div>

Great, now we have multiple versions of our React App running at the same time! This is pretty much the foundation for this article ⚡️

Passing Data Attributes

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So we have our React App rendering multiple times in a page. This within itself isn't useful. We want each instance of our app to contain different data or functionality.

There are tons of ways to pass data to and from a React App. In this article, we'll cover using data attributes.

Reading DOM attributes in a React component

In React, we use Props to attach useful data to our components. In HTML, we have data attributes. Which, together with a bit of JavaScript, can be just as powerful.

First, let's attach some data attributes to our DOM elements in public/index.html.

<div class="reddit_widget" data-subreddit="javascript"></div>
<div class="reddit_widget" data-subreddit="reactjs"></div>

Now, let's read those data attributes in our React App. There are a number of ways we can do this.

We can use Div.getAttribute("data-subreddit") to get our attribute from each DOM element. We can pass this a subreddit prop to our React <App/> component.
Similar to option 1, but using the dataset property (IE: Div.dataset.subreddit).
We can pass the entire DOM element as a prop, to our React <App /> component. Allowing us to access the entire DOM element for each App. From there, we can do anything with the dom element. Including getting the attributes.

For more information, check out using data attributes.

For this article, We'll go with option 3.

// index.js 

WidgetDivs.forEach(Div => {
  ReactDOM.render(
    <React.StrictMode>
      <App domElement={Div} />
    </React.StrictMode>,
    Div
  );
})

// src/App.js 

function App({ domElement }) {
  const subreddit = domElement.getAttribute("data-subreddit")

  return (
    <div className="App">
      <header className="App-header">
        <img src={logo} className="App-logo" alt="logo" />
        <p>
          My favorite subreddit is /r/{subreddit}
        </p>
        <a
          className="App-link"
          href="https://reactjs.org"
          target="_blank"
          rel="noopener noreferrer"
        >
          Learn React
        </a>
      </header>
    </div>
  );
}

Great! Now we are successfully passing data from the DOM to our React App. This opens the door to tons of possibilities. We can create entirely different versions of our app, based on the attributes passed from the DOM 😆

Example of a "real world" reddit widget

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For the sake of this article, I'll assume you're already familiar with a few basic React concepts. IE: Data Fetching as well as Components and Props. So I won't dive into the changes made to pull data from Reddit's API & display the lists. If you'd like a separate article on this, please comment below. However, I feel this is already covered extensively.

To make this widget even more useful and "complete", we'll fetch some data from Reddit's API. We want to include some of the latest posts, along with links to them. We also want to include a link to the subreddit itself. Finally, it's common practice for widgets to include a "powered by" notice. Especially in a "freemium" pricing model. This allows other people to discover your widget and also become customers. Maybe even paying customers.

Here's an example of what that looks like.

import React, { useEffect, useState } from 'react';
import './App.css';

// Render each post
function renderPost(post){
  const { data: { title, url, author, id } } = post
  const authorUrl = `https://www.reddit.com/u/${author}`

  return (
    <div className="reddit_widget__post" key={id}>
      <div className="reddit_widget__posted_by">
        posted by <a href={authorUrl} className="reddit_widget__posted_by" target="_blank" rel="noopener noreferrer">u/{author}</a>
      </div>
      <a href={url} className="reddit_widget__title" target="_blank" rel="noopener noreferrer">{title}</a>
    </div>
  )
}

// Filter, since reddit always returns stickied posts up top
function nonStickiedOnly(post){
  return !post.data.stickied
}

function App({ domElement }) {
  const subreddit = domElement.getAttribute("data-subreddit")
  const [loading, setLoading] = useState();
  const [error, setError] = useState('');
  const [data, setData] = useState([]);

  useEffect(() => {
    // Fetch data from reddit
    setLoading(true)
    fetch(`https://www.reddit.com/r/${subreddit}.json`)
      .then((response) => response.json())
      .then((data) => {
        setLoading(false);
        setData(data.data.children.slice(0, 10));
      })
      .catch((e) => {
        console.log(e)
        setLoading(false);
        setError('error fetching from reddit');
      });
  }, [ subreddit ])

  return (
    <div className="reddit_widget__app">
      <h1 className="reddit_widget__header">
        Latest posts in <a href={`https://reddit.com/r/${subreddit}`} rel="noopener noreferrer">/r/{subreddit}</a>
      </h1>
      <div className="reddit_widget__inner">
        {loading && "Loading..."}
        {error && error}
        {!!data.length && data.filter(nonStickiedOnly).map(renderPost)}
      </div>
      <p className="reddit_widget__powered_by">
        This widget is powered by{" "}
        <a
          href="https://javascriptpros.com"
          rel="noopener noreferrer"
          target="_blank"
        >
          JavaScriptPros.com
        </a>
      </p>
    </div>
  );
}

export default App;

Building our widget

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We initialized our app using create-react-app. For the sake of getting our entire bundle into a single JS & CSS file, we'll build using parcel. Instead of completely replacing our build script, we'll add a new one called build:widget. In this article, we won't dive too deep into how parcel works, but feel free to check it out.

First, add parcel as a dependency

yarn add --dev parcel-bundler

Update package.json with a new build script. This tells parcel to build our JS (which will also build our css) into our docs directory. Source maps won't be needed, to keep our build small. We chose the docs directory, so that we can publish our widget using GitHub pages, but any directory works.

"build:widget": "parcel build src/index.js --no-source-maps -d docs",

You may also want to ignore the cache directory parcel uses in .gitignore

# .gitignore

# parcel 
.cache

See our widget in action

The full code, including styling, can be seen here. You can also demo the widget itself here.

And here's what that looks like 🧐

(note: at the time of writing, the image below is broken, here is a direct link)

Enabling non-developers to use our widget

When providing instructions to a customer on how to use the widget, we'd probably send them instructions that look something like this:

Copy these 3 lines of code and replace SUBREDDIT_HERE with the subreddit of your liking.
You can add more than one widget by duplicating only the 3rd line.

<link href="https://giologist.github.io/article-react-reddit-widget/index.css" rel="stylesheet" />
<script src="https://giologist.github.io/article-react-reddit-widget/index.js"></script>
<div class="reddit_widget" data-subreddit="SUBREDDIT_HERE"></div>

Things to consider

React may not always be necessary, or the best tool for a smaller widget. If keeping bundle size down is your main priority, you may want to consider building your widget simply using vanilla javascript.
If your widget is going to load its own css, be sure not to include style properties for common elements such as html and body. You don't want to override the styling on someone else's page. Keep your styling specific to only your widget.

Any questions? Feel free to drop a comment.

Hostman - Create & Deploy a React App in under 4 minutes (from scratch)

Gio — Thu, 30 Jul 2020 15:38:18 +0000

Hostman

I stumbled across Hostman on Reddit and was quickly amazed with how fast it was to get going. I can honestly say that this was the first time I've deployed to to a Cloud Hosting app, before even having a password set up on that Cloud Hosting app.

In the video below, I'll walk you through deploying a React App on Hostman in just a few minutes. From start to finish. We initialize the React App, make a GitHub repo and deploy all from scratch.

Happy hacking!

React Native: Comparing popular Component Libraries

Gio — Wed, 22 Jul 2020 22:41:55 +0000

Component libraries are naturally one of the first things developers reach for when starting a React Native project. There's something slightly underwhelming about being excited to start a new project, only to find yourself building the same type of component over and over again.

When picking a component library, there are a few things to consider.

How friendly is the API? It’s easy to get caught up in the look and feel of a component library. However, any well developed component library should be relatively easy to customize to your liking. What’s perhaps more important is how comfortable you are with the API. Do you agree with the decisions made by those who made the library? Does it feel natural when using it for a bit? Or do you find yourself struggling to implement it, even after reading the docs and getting a better understanding? Always experiment with a few component libraries, to see which suits you best (that's what we'll be doing in this article : ) ).
Do you like the base design provided? Some React Native component libraries, such as material kit react native are very opinionated with the out-of-the-box styling they provide. Others, such as native base don't focus too much on the styling. Rather, they just provide a set of basic components. Leaving the composition and styling of components up to you. Different requirements call for different component libraries.

The goal of this article is not to answer these questions for you. Instead, we'll explore a few different React Native component libraries, in a way that'll allow you to answer these questions for yourself. We'll build a Card component, which is very common in any code-base. By constructing the Card component, we'll interact with the API directly. Allowing us to determine how much we enjoy working with the component libary. Upon completion, we can take a step back and see if we agree with the base design provided.

Native Base

Native Base is a component library with a focus on a cross-platform "native" feel. Instead of making fancy design decisions for you, Native Base provides a set of basic components which are styled specifically to their platform.

For example, check out what a "Header" component looks like on iOS vs Android.

Note: The original version of this article includes an embedded snack. Since dev.to does not have expo snack support, we've modified this version to just have a link.

View the Snack

React Native Elements

React Native Elements is a component library that's 100% community driven. It provides over 20 basic components, suitable to bootstrap any project. The components provided appear the same regardless of the platform. For example, a Header component looks the same on both iOS and Android.

Notice the difference in the React Native Elements Card below, compared to NativeBase above. In the React Native Elements Card Component, there's a built in Image prop. This automatically inserts the image at the top of the card. There are ways to make our Card identical to the one we built above. However, let's not try and force a specific design. Instead, let's embrace the differences between the two packages. Allowing us to get a better feel for the API & design decisions made.

Note: The original version of this article includes an embedded snack. Since dev.to does not have expo snack support, we've modified this version to just have a link.

View the Snack

UI Kitten

UI Kitten is a component library with a strong emphasis on theming and design systems. All of this is highly configurable, but it comes at a cost. When setting up UI Kitten on your react native app, there are additional steps involved to integrate the component library. You must wrap your app in an ApplicationProvider component. This is where you define the theme in which it will be using. UI Kitten allows you to use their very own "Eva" theme, or a "Material" theme. Both come with light & dark versions as well.

Additionally, the documentation for UI Kitten is beautiful and has live previews every step of the way. The live previews even allow you to switch between themes and light/dark mode. Check out the Card component documentation, for example. And of course, check out the Card component we made below 🤓

Note: The original version of this article includes an embedded snack. Since dev.to does not have expo snack support, we've modified this version to just have a link.

View the Snack

More component libraries being added soon!

You can expect this post to be updated with more component libraries as time passes. We will be updating this regularly : )

Want to be notified whenever we add more component libraries? Subscribe here.

Have a React Native component library you'd like added here? Drop us a message