React Tips — Radio Buttons, Render HTML, and Initialize States

React is a popular library for creating web apps and mobile apps.

In this article, we’ll look at some tips for writing better React apps.

Insert HTML with React

We can insert HTML in our React code.

To do that, we use the dangerouslySetInnerHTNL prop.

For instance, we can write:

render() {
  return (
    <div dangerouslySetInnerHTML={{ __html: someHtml }}></div>
    );
}

We pass in an object with the __html property to render raw HTML.

someHtml is a string with the HTML content.

Initialize State from Props in a React Component

We can initialize the state from props in a React component by setting this.state in the constructor.

For instance, we can write:

class App extends React.Component {

  constructor(props) {
    super(props);
    this.state = {
      x: props.initialX
    };
  }
  // ...
}

We get the props from the props parameter and set it as a property of this.state .

#web-development #javascript #software-development #programming #technology

How native is React Native? | React Native vs Native App Development

If you are undertaking a mobile app development for your start-up or enterprise, you are likely wondering whether to use React Native. As a popular development framework, React Native helps you to develop near-native mobile apps. However, you are probably also wondering how close you can get to a native app by using React Native. How native is React Native?

In the article, we discuss the similarities between native mobile development and development using React Native. We also touch upon where they differ and how to bridge the gaps. Read on.

A brief introduction to React Native

Let’s briefly set the context first. We will briefly touch upon what React Native is and how it differs from earlier hybrid frameworks.

React Native is a popular JavaScript framework that Facebook has created. You can use this open-source framework to code natively rendering Android and iOS mobile apps. You can use it to develop web apps too.

Facebook has developed React Native based on React, its JavaScript library. The first release of React Native came in March 2015. At the time of writing this article, the latest stable release of React Native is 0.62.0, and it was released in March 2020.

Although relatively new, React Native has acquired a high degree of popularity. The “Stack Overflow Developer Survey 2019” report identifies it as the 8th most loved framework. Facebook, Walmart, and Bloomberg are some of the top companies that use React Native.

The popularity of React Native comes from its advantages. Some of its advantages are as follows:

Performance: It delivers optimal performance.
Cross-platform development: You can develop both Android and iOS apps with it. The reuse of code expedites development and reduces costs.
UI design: React Native enables you to design simple and responsive UI for your mobile app.
3rd party plugins: This framework supports 3rd party plugins.
Developer community: A vibrant community of developers support React Native.

Why React Native is fundamentally different from earlier hybrid frameworks

Are you wondering whether React Native is just another of those hybrid frameworks like Ionic or Cordova? It’s not! React Native is fundamentally different from these earlier hybrid frameworks.

React Native is very close to native. Consider the following aspects as described on the React Native website:

Access to many native platforms features: The primitives of React Native render to native platform UI. This means that your React Native app will use many native platform APIs as native apps would do.
Near-native user experience: React Native provides several native components, and these are platform agnostic.
The ease of accessing native APIs: React Native uses a declarative UI paradigm. This enables React Native to interact easily with native platform APIs since React Native wraps existing native code.

Due to these factors, React Native offers many more advantages compared to those earlier hybrid frameworks. We now review them.

#android app #frontend #ios app #mobile app development #benefits of react native #is react native good for mobile app development #native vs #pros and cons of react native #react mobile development #react native development #react native experience #react native framework #react native ios vs android #react native pros and cons #react native vs android #react native vs native #react native vs native performance #react vs native #why react native #why use react native

Phoebe Shanahan

1596090360

Types, Effects and Attributes

HTML Button Tag – Types, Effects and Attributes

In this article, we are going to learn HTML Button Tags. So let’s start!!!

HTML Button

The

#html tutorials #html button #html button attributes #html button element #html button tags #html

Mikayla Bashirian

1596090900

HTML Radio Button - Radio Group and Attributes

HTML Radio button is typically used to select a particular option from a group of related options. To define a radio button, we use the element of HTML. When a particular option is selected using a radio button, the other options are deselected i.e., one can only select a single option at a time. It lets the user select from a set of limited options.

Syntax of HTML Radio Button:

Radio buttons belonging to a particular category must have the same name. The value of each radio button is not shown to the user but is sent to the server after its selection by the user. It is a good practice to use a tag along with radio buttons for better accessibility.

Defining Radio Group in HTML

We can define a group for radio buttons by giving each radio button the same name. As and when the user selects a particular option from this group, other options are deselected.

Following is an example of radio buttons with different names within a form.

<html>
<head>
  <title>Radio Buttons</title>
</head>
<body>
<form>
  <p>Please select your preferred contact method</p>
  <div>
    <input type="radio" id="contactChoice1"
     name="contact" value="email">
    <label for="Choice1">Email</label>
    <input type="radio" id="contactChoice2"
     name="contact" value="phone">
    <label for="Choice2">Phone</label>
    <input type="radio" id="contactChoice3"
     name="contact" value="mail">
    <label for="Choice3">Mail</label>
  </div>
  <div>
    <button type="submit">Submit</button>
  </div>
</form>
</body>
</html>

Output-

Attributes of HTML Radio Group

NameDescriptiontypeSpecifies the type of input, in this case set as ‘radio’.nameSpecifies the name of the control that is delivered to the server.valueSpecifies the value that will be sent to the server, if the radio button is checked.checkedDefines a by default checked radio button.

We should specify the value attribute so that the information is delivered to the server, on form submission. If the value attribute is not specified, the form data assigns a value ‘on’ to the entire radio group (this isn’t a good practice).

Selecting Radio Button by default

If no radio button is selected by the user, no information of the radio buttons is delivered to the server. Hence, it is recommended to use the ‘checked’ state of the radio button and eliminate inefficiency.

<html>
<head>
  <title>Radio Buttons</title>
</head>
<body>
<form>
  <p>Please select your preferred contact method</p>
  <div>
    <input type="radio" id="contactChoice1"
     name="contact" value="email" checked>
    <label for="Choice1">Email</label>
    <input type="radio" id="contactChoice2"
     name="contact" value="phone">
    <label for="Choice2">Phone</label>
    <input type="radio" id="contactChoice3"
     name="contact" value="mail">
    <label for="Choice3">Mail</label>
  </div>
  <div>
    <button type="submit">Submit</button>
  </div>
</form>
</body>
</html>

Output-

If ‘checked’ is put along with every button, the one put later overrides the ones put before it.

CSS and Radio Buttons

We can style radio buttons using CSS3.

<html>
<head>
  <title>Radio Buttons</title>
  <style>
    label {
  margin-right: 15px;
  line-height: 32px;
}
    input {
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;

  border-radius: 50%;
  width: 16px;
  height: 16px;

  border: 2px solid #999;
  transition: 0.2s all linear;
  margin-right: 5px;

  position: relative;
  top: 4px;
}
  </style>
</head>
<body>
<form> 
  <p>Please select your preferred contact method:</p>
  <div>
    <input type="radio" id="contactChoice1"
           name="contact" value="email">
    <label for="contactChoice1">Email</label>
    <input type="radio" id="contactChoice2"
           name="contact" value="phone">
    <label for="contactChoice2">Phone</label>
    <input type="radio" id="contactChoice3"
           name="contact" value="mail">
    <label for="contactChoice3">Mail</label>
  </div>
  <div>
    <button type="submit">Submit</button>
  </div>
</form>
<pre id="log">
</pre>
</body>
</html>

#html tutorials #html radio button #javascript and radio buttons

Lambert Goldner

1652736240

React-rails: integrate React.js with Rails Views and Controllers

React-Rails

React-Rails is a flexible tool to use React with Rails. The benefits:

Automatically renders React server-side and client-side
Supports Webpacker 4.x, 3.x, 2.x, 1.1+
Supports Sprockets 4.x, 3.x, 2.x
Lets you use JSX, ES6, TypeScript, CoffeeScript

Get started with Webpacker

Alternatively, get started with Sprockets

Webpacker provides modern JS tooling for Rails. Here are the listed steps for integrating Webpacker and Rails-React with Rails:

1) Create a new Rails app:

$ rails new my-app
$ cd my-app

2) Add react-rails to your Gemfile:

gem 'react-rails'

Note: On rails versions < 6.0, You need to add gem 'webpacker' to your Gemfile in step 2 above.

3) Now run the installers:

Rails 6.x and 5.x:

$ bundle install
$ rails webpacker:install         # OR (on rails version < 5.0) rake webpacker:install
$ rails webpacker:install:react   # OR (on rails version < 5.0) rake webpacker:install:react
$ rails generate react:install

This gives you:

app/javascript/components/ directory for your React components
ReactRailsUJS setup in app/javascript/packs/application.js
app/javascript/packs/server_rendering.js for server-side rendering

Note: On rails versions < 6.0, link the JavaScript pack in Rails view using javascript_pack_tag helper:

<!-- application.html.erb in Head tag below turbolinks -->
<%= javascript_pack_tag 'application' %>

4) Generate your first component:

$ rails g react:component HelloWorld greeting:string

5) You can also generate your component in a subdirectory:

$ rails g react:component my_subdirectory/HelloWorld greeting:string

Note: Your component is added to app/javascript/components/ by default.

Note: If your component is in a subdirectory you will append the directory path to your erb component call.

Example:

<%= react_component("my_subdirectory/HelloWorld", { greeting: "Hello from react-rails." }) %>

6) Render it in a Rails view:

<!-- erb: paste this in view -->
<%= react_component("HelloWorld", { greeting: "Hello from react-rails." }) %>

7) Lets Start the app:

$ rails s

output: greeting: Hello from react-rails", inspect webpage in your browser too see change in tag props.

Component name

The component name tells react-rails where to load the component. For example:

`react_component` call	component `require`
`react_component("Item")`	`require("Item")`
`react_component("items/index")`	`require("items/index")`
`react_component("items.Index")`	`require("items").Index`
`react_component("items.Index.Header")`	`require("items").Index.Header`

This way, you can access top-level, default, or named exports.

The require.context inserted into packs/application.js is used to load components. If you want to load components from a different directory, override it by calling ReactRailsUJS.useContext:

var myCustomContext = require.context("custom_components", true)
var ReactRailsUJS = require("react_ujs")
// use `custom_components/` for <%= react_component(...) %> calls
ReactRailsUJS.useContext(myCustomContext)

If require fails to find your component, ReactRailsUJS falls back to the global namespace, described in Use with Asset Pipeline.

File naming

React-Rails supports plenty of file extensions such as: .js, .jsx.js, .js.jsx, .es6.js, .coffee, etcetera! Sometimes this will cause a stumble when searching for filenames.

Component File Name	`react_component` call
`app/javascript/components/samplecomponent.js`	`react_component("samplecomponent")`
`app/javascript/components/sample_component.js`	`react_component("sample_component")`
`app/javascript/components/SampleComponent.js`	`react_component("SampleComponent")`
`app/javascript/components/SampleComponent.js.jsx`	Has to be renamed to SampleComponent.jsx, then use `react_component("SampleComponent")`

Typescript support

If you want to use React-Rails with Typescript, simply run the installer and add @types:

$ bundle exec rails webpacker:install:typescript
$ yarn add @types/react @types/react-dom

Doing this will allow React-Rails to support the .tsx extension. Additionally, it is recommended to add ts and tsx to the server_renderer_extensions in your application configuration:

config.react.server_renderer_extensions = ["jsx", "js", "tsx", "ts"]

Test component

You can use assert_react_component to test component render:

app/views/welcome/index.html.erb

<%= react_component("HelloWorld", { greeting: "Hello from react-rails.", info: { name: "react-rails" } }, { class: "hello-world" }) %>

class WelcomeControllerTest < ActionDispatch::IntegrationTest
  test 'assert_react_component' do
    get "/welcome"
    assert_equal 200, response.status

    # assert rendered react component and check the props
    assert_react_component "HelloWorld" do |props|
      assert_equal "Hello from react-rails.", props[:greeting]
      assert_equal "react-rails", props[:info][:name]
      assert_select "[class=?]", "hello-world"
    end

    # or just assert component rendered
    assert_react_component "HelloWorld"
  end
end

Use with Asset Pipeline

react-rails provides a pre-bundled React.js & a UJS driver to the Rails asset pipeline. Get started by adding the react-rails gem:

gem 'react-rails'

And then install the react generator:

$ rails g react:install

Then restart your development server.

This will:

add some //= requires to application.js
add a components/ directory for React components
add server_rendering.js for server-side rendering

Now, you can create React components in .jsx files:

// app/assets/javascripts/components/post.jsx

window.Post = createReactClass({
  render: function() {
    return <h1>{this.props.title}</h1>
  }
})

// or, equivalent:
class Post extends React.Component {
  render() {
    return <h1>{this.props.title}</h1>
  }
}

Then, you can render those components in views:

<%= react_component("Post", {title: "Hello World"}) %>

Components must be accessible from the top level, but they may be namespaced, for example:

<%= react_component("Comments.NewForm", {post_id: @post.id}) %>
<!-- looks for `window.Comments.NewForm` -->

Custom JSX Transformer

react-rails uses a transformer class to transform JSX in the asset pipeline. The transformer is initialized once, at boot. You can provide a custom transformer to config.react.jsx_transformer_class. The transformer must implement:

#initialize(options), where options is the value passed to config.react.jsx_transform_options
#transform(code_string) to return a string of transformed code

react-rails provides two transformers, React::JSX::BabelTransformer (which uses ruby-babel-transpiler) and React::JSX::JSXTransformer (which uses the deprecated JSXTransformer.js).

Transform Plugin Options

To supply additional transform plugins to your JSX Transformer, assign them to config.react.jsx_transform_options

react-rails uses the Babel version of the babel-source gem.

For example, to use babel-plugin-transform-class-properties :

config.react.jsx_transform_options = {
  optional: ['es7.classProperties']
}

React.js versions

//= require react brings React into your project.

By default, React's [development version] is provided to Rails.env.development. You can override the React build with a config:

# Here are the defaults:
# config/environments/development.rb
MyApp::Application.configure do
  config.react.variant = :development
end

# config/environments/production.rb
MyApp::Application.configure do
  config.react.variant = :production
end

Be sure to restart your Rails server after changing these files. See VERSIONS.md to learn which version of React.js is included with your react-rails version. In some edge cases you may need to bust the sprockets cache with rake tmp:clear

View Helper

react-rails includes a view helper and an unobtrusive JavaScript driver which work together to put React components on the page.

The view helper (react_component) puts a div on the page with the requested component class & props. For example:

<%= react_component('HelloMessage', name: 'John') %>
<!-- becomes: -->
<div data-react-class="HelloMessage" data-react-props="{&quot;name&quot;:&quot;John&quot;}"></div>

On page load, the react_ujs driver will scan the page and mount components using data-react-class and data-react-props.

The view helper's signature is:

react_component(component_class_name, props={}, html_options={})

component_class_name is a string which identifies a component. See getConstructor for details.
props is either:
- an object that responds to #to_json; or
- an already-stringified JSON object (see JBuilder note below).
html_options may include:
- tag: to use an element other than a div to embed data-react-class and data-react-props.
- prerender: true to render the component on the server.
- camelize_props to transform a props hash
- **other Any other arguments (eg class:, id:) are passed through to content_tag.

Custom View Helper

react-rails uses a "helper implementation" class to generate the output of the react_component helper. The helper is initialized once per request and used for each react_component call during that request. You can provide a custom helper class to config.react.view_helper_implementation. The class must implement:

#react_component(name, props = {}, options = {}, &block) to return a string to inject into the Rails view
#setup(controller_instance), called when the helper is initialized at the start of the request
#teardown(controller_instance), called at the end of the request

react-rails provides one implementation, React::Rails::ComponentMount.

UJS

react-rails's JavaScript is available as "react_ujs" in the asset pipeline or from NPM. It attaches itself to the window as ReactRailsUJS.

Mounting & Unmounting

Usually, react-rails mounts & unmounts components automatically as described in Event Handling below.

You can also mount & unmount components from <%= react_component(...) %> tags using UJS:

// Mount all components on the page:
ReactRailsUJS.mountComponents()
// Mount components within a selector:
ReactRailsUJS.mountComponents(".my-class")
// Mount components within a specific node:
ReactRailsUJS.mountComponents(specificDOMnode)

// Unmounting works the same way:
ReactRailsUJS.unmountComponents()
ReactRailsUJS.unmountComponents(".my-class")
ReactRailsUJS.unmountComponents(specificDOMnode)

You can use this when the DOM is modified by AJAX calls or modal windows.

Event Handling

ReactRailsUJS checks for various libraries to support their page change events:

Turbolinks
pjax
jQuery
Native DOM events

ReactRailsUJS will automatically mount components on <%= react_component(...) %> tags and unmount them when appropriate.

If you need to re-detect events, you can call detectEvents:

// Remove previous event handlers and add new ones:
ReactRailsUJS.detectEvents()

For example, if Turbolinks is loaded after ReactRailsUJS, you'll need to call this again. This function removes previous handlers before adding new ones, so it's safe to call as often as needed.

If Turbolinks is imported via Webpacker (and thus not available globally), ReactRailsUJS will be unable to locate it. To fix this, you can temporarily add it to the global namespace:

// Order is particular. First start Turbolinks:
Turbolinks.start();
// Add Turbolinks to the global namespace:
window.Turbolinks = Turbolinks;
// Remove previous event handlers and add new ones:
ReactRailsUJS.detectEvents();
// (Optional) Clean up global namespace:
delete window.Turbolinks;

`getConstructor`

Components are loaded with ReactRailsUJS.getConstructor(className). This function has two built-in implementations:

On the asset pipeline, it looks up className in the global namespace.
On Webpacker, it requires files and accesses named exports, as described in Get started with Webpacker.

You can override this function to customize the mapping of name-to-constructor. Server-side rendering also uses this function.

Server-Side Rendering

You can render React components inside your Rails server with prerender: true:

<%= react_component('HelloMessage', {name: 'John'}, {prerender: true}) %>
<!-- becomes: -->
<div data-react-class="HelloMessage" data-react-props="{&quot;name&quot;:&quot;John&quot;}">
  <h1>Hello, John!</h1>
</div>

(It will also be mounted by the UJS on page load.)

Server rendering is powered by ExecJS and subject to some requirements:

react-rails must load your code. By convention, it uses server_rendering.js, which was created by the install task. This file must include your components and their dependencies (eg, Underscore.js).
Your code can't reference document or window. Prerender processes don't have access to document or window, so jQuery and some other libs won't work in this environment :(

ExecJS supports many backends. CRuby users will get the best performance from mini_racer.

Configuration

Server renderers are stored in a pool and reused between requests. Threaded Rubies (eg jRuby) may see a benefit to increasing the pool size beyond the default 0.

These are the default configurations:

# config/application.rb
# These are the defaults if you don't specify any yourself
module MyApp
  class Application < Rails::Application
    # Settings for the pool of renderers:
    config.react.server_renderer_pool_size  ||= 1  # ExecJS doesn't allow more than one on MRI
    config.react.server_renderer_timeout    ||= 20 # seconds
    config.react.server_renderer = React::ServerRendering::BundleRenderer
    config.react.server_renderer_options = {
      files: ["server_rendering.js"],       # files to load for prerendering
      replay_console: true,                 # if true, console.* will be replayed client-side
    }
    # Changing files matching these dirs/exts will cause the server renderer to reload:
    config.react.server_renderer_extensions = ["jsx", "js"]
    config.react.server_renderer_directories = ["/app/assets/javascripts", "/app/javascript/"]
  end
end

JavaScript State

Some of ExecJS's backends are stateful (eg, mini_racer, therubyracer). This means that any side-effects of a prerender will affect later renders with that renderer.

To manage state, you have a couple options:

Make a custom renderer with #before_render / #after_render hooks as described below
Use per_request_react_rails_prerenderer to manage state for a whole controller action.

To check out a renderer for the duration of a controller action, call the per_request_react_rails_prerenderer helper in the controller class:

class PagesController < ApplicationController
  # Use the same React server renderer for the entire request:
  per_request_react_rails_prerenderer
end

Then, you can access the ExecJS context directly with react_rails_prerenderer.context:

def show
  react_rails_prerenderer           # => #<React::ServerRendering::BundleRenderer>
  react_rails_prerenderer.context   # => #<ExecJS::Context>

  # Execute arbitrary JavaScript code
  # `self` is the global context
  react_rails_prerenderer.context.exec("self.Store.setup()")
  render :show
  react_rails_prerenderer.context.exec("self.Store.teardown()")
end

react_rails_prerenderer may also be accessed in before- or after-actions.

Custom Server Renderer

react-rails depends on a renderer class for rendering components on the server. You can provide a custom renderer class to config.react.server_renderer. The class must implement:

#initialize(options={}), which accepts the hash from config.react.server_renderer_options
#render(component_name, props, prerender_options) to return a string of HTML

react-rails provides two renderer classes: React::ServerRendering::ExecJSRenderer and React::ServerRendering::BundleRenderer.

ExecJSRenderer offers two other points for extension:

#before_render(component_name, props, prerender_options) to return a string of JavaScript to execute before calling React.render
#after_render(component_name, props, prerender_options) to return a string of JavaScript to execute after calling React.render

Any subclass of ExecJSRenderer may use those hooks (for example, BundleRenderer uses them to handle console.* on the server).

Controller Actions

Components can also be server-rendered directly from a controller action with the custom component renderer. For example:

class TodoController < ApplicationController
  def index
    @todos = Todo.all
    render component: 'TodoList', props: { todos: @todos }, tag: 'span', class: 'todo'
  end
end

You can also provide the "usual" render arguments: content_type, layout, location and status. By default, your current layout will be used and the component, rather than a view, will be rendered in place of yield. Custom data-* attributes can be passed like data: {remote: true}.

Prerendering is set to true by default, but can be turned off with prerender: false.

Component Generator

You can generate a new component file with:

rails g react:component ComponentName prop1:type prop2:type ...

For example,

rails g react:component Post title:string published:bool published_by:instanceOf{Person}

would generate:

var Post = createReactClass({
  propTypes: {
    title: PropTypes.string,
    published: PropTypes.bool,
    publishedBy: PropTypes.instanceOf(Person)
  },

  render: function() {
    return (
      <React.Fragment>
        Title: {this.props.title}
        Published: {this.props.published}
        Published By: {this.props.publishedBy}
      </React.Fragment>
    );
  }
});

The generator also accepts options:

--es6: use class ComponentName extends React.Component
--coffee: use CoffeeScript

Accepted PropTypes are:

Plain types: any, array, bool, element, func, number, object, node, shape, string
instanceOf takes an optional class name in the form of instanceOf{className}.
oneOf behaves like an enum, and takes an optional list of strings in the form of 'name:oneOf{one,two,three}'.
oneOfType takes an optional list of react and custom types in the form of 'model:oneOfType{string,number,OtherType}'.

Note that the arguments for oneOf and oneOfType must be enclosed in single quotes to prevent your terminal from expanding them into an argument list.

Use with JBuilder

If you use Jbuilder to pass a JSON string to react_component, make sure your JSON is a stringified hash, not an array. This is not the Rails default -- you should add the root node yourself. For example:

# BAD: returns a stringified array
json.array!(@messages) do |message|
  json.extract! message, :id, :name
  json.url message_url(message, format: :json)
end

# GOOD: returns a stringified hash
json.messages(@messages) do |message|
  json.extract! message, :id, :name
  json.url message_url(message, format: :json)
end

Camelize Props

You can configure camelize_props option:

MyApp::Application.configure do
  config.react.camelize_props = true # default false
end

Now, Ruby hashes given to react_component(...) as props will have their keys transformed from underscore- to camel-case, for example:

{ all_todos: @todos, current_status: @status }
# becomes:
{ "allTodos" => @todos, "currentStatus" => @status }

You can also specify this option in react_component:

<%= react_component('HelloMessage', {name: 'John'}, {camelize_props: true}) %>

Upgrading

2.3 to 2.4

Keep your react_ujs up to date, yarn upgrade

React-Rails 2.4.x uses React 16+ which no longer has React Addons. Therefore the pre-bundled version of react no longer has an addons version, if you need addons still, there is the 2.3.1+ version of the gem that still has addons.

If you need to make changes in your components for the prebundled react, see the migration docs here:

For the vast majority of cases this will get you most of the migration:

global find+replace React.Prop -> Prop
add import PropTypes from 'prop-types' (Webpacker only)
re-run bundle exec rails webpacker:install:react to update npm packages (Webpacker only)

Common Errors

During installation

While using installers.(rails webpacker:install:react && rails webpacker:install) Error:

public/packs/manifest.json. Possible causes:
1. You want to set webpacker.yml value of compile to true for your environment
   unless you are using the `webpack -w` or the webpack-dev-server.
2. webpack has not yet re-run to reflect updates.
3. You have misconfigured Webpacker's config/webpacker.yml file.
4. Your webpack configuration is not creating a manifest.
or
yarn: error: no such option: --dev
ERROR: [Errno 2] No such file or directory: 'add'

Fix: Try updating yarn package.

sudo apt remove cmdtest
sudo apt remove yarn
curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
sudo apt-get update && sudo apt-get install yarn

yarn install

Undefined Set

ExecJS::ProgramError (identifier 'Set' undefined):

(execjs):1

If you see any variation of this issue, see Using TheRubyRacer

Using TheRubyRacer

TheRubyRacer hasn't updated LibV8 (The library that powers Node.js) from v3 in 2 years, any new features are unlikely to work.

LibV8 itself is already beyond version 7 therefore many serverside issues are caused by old JS engines and fixed by using an up to date one such as MiniRacer or TheRubyRhino on JRuby.

HMR

Hot Module Replacement is possible with this gem as it does just pass through to Webpacker. Please open an issue to let us know tips and tricks for it to add to the wiki.

Sample repo that shows HMR working with react-rails: https://github.com/edelgado/react-rails-hmr

One caveat is that currently you cannot Server-Side Render along with HMR.

Related Projects

webpacker-react: Integration of React with Rails utilizing Webpack with Hot Module Replacement (HMR).
The React on Rails Course A video course which teaches the basics of React and how to get started using it in Rails with react-rails.
react_on_rails: Integration of React with Rails utilizing Webpack, Redux, React-Router.
react-rails-hot-loader Simple live-reloader for react-rails.
react-rails-benchmark_renderer adds performance instrumentation to server rendering.
Ruby Hyperstack: Use Ruby to build reactive user interfaces with React.

Contributing

🎉 Thanks for taking the time to contribute! 🎉

With 5 Million+ downloads of the react-rails Gem and another 2 Million+ downloads of react_ujs on NPM, you're helping the biggest React + Rails community!

By contributing to React-Rails, you agree to abide by the code of conduct.

You can always help by submitting patches or triaging issues, even offering reproduction steps to issues is incredibly helpful!

Please see our Contribution guide for more info.

A source code example utilizing React-Rails: https://github.com/BookOfGreg/react-rails-example-app

Author: Reactjs
Source Code: https://github.com/reactjs/react-rails
License: Apache-2.0 license

#react #javascript #typescript #ruby #rails

Ava Watson

1595318322

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