Inertia Coder

Inertia.js + Rails

Build modern single-page applications using Inertia.js with React/Vue/Svelte and Rails backend.

When to Use This Skill

• Setting up Inertia.js with Rails
• Creating Inertia page components
• Handling forms with useForm hook
• Managing shared props and flash messages
• Client-side routing without API complexity
• File uploads with progress tracking

What is Inertia.js?

Inertia.js allows you to build SPAs using classic server-side routing and controllers.

Quick Setup

# Gemfile
gem 'inertia_rails'
gem 'vite_rails'

bundle install
rails inertia:install  # Choose: React, Vue, or Svelte

# config/initializers/inertia_rails.rb
InertiaRails.configure do |config|
  config.version = ViteRuby.digest

  config.share do |controller|
    {
      auth: {
        user: controller.current_user&.as_json(only: [:id, :name, :email])
      },
      flash: controller.flash.to_hash
    }
  end
end

Controller Pattern

class ArticlesController < ApplicationController
  def index
    articles = Article.published.order(created_at: :desc)

    render inertia: 'Articles/Index', props: {
      articles: articles.as_json(only: [:id, :title, :excerpt])
    }
  end

  def create
    @article = Article.new(article_params)

    if @article.save
      redirect_to article_path(@article), notice: 'Article created'
    else
      redirect_to new_article_path, inertia: { errors: @article.errors }
    end
  end
end

React Page Component

// app/frontend/pages/Articles/Index.jsx
import { Link } from '@inertiajs/react'

export default function Index({ articles }) {
  return (
    <div>
      <h1>Articles</h1>
      {articles.map(article => (
        <Link key={article.id} href={`/articles/${article.id}`}>
          <h2>{article.title}</h2>
        </Link>
      ))}
    </div>
  )
}

Forms with useForm

import { useForm } from '@inertiajs/react'

export default function New() {
  const { data, setData, post, processing, errors } = useForm({
    title: '',
    body: ''
  })

  function handleSubmit(e) {
    e.preventDefault()
    post('/articles')
  }

  return (
    <form
      <input
        value={data.title}
        => setData('title', e.target.value)}
      />
      {errors.title && <div className="error">{errors.title}</div>}

      <textarea
        value={data.body}
        => setData('body', e.target.value)}
      />
      {errors.body && <div className="error">{errors.body}</div>}

      <button disabled={processing}>
        {processing ? 'Creating...' : 'Create'}
      </button>
    </form>
  )
}

Shared Layout

// app/frontend/layouts/AppLayout.jsx
import { Link, usePage } from '@inertiajs/react'

export default function AppLayout({ children }) {
  const { auth, flash } = usePage().props

  return (
    <div>
      <nav>
        <Link href="/">Home</Link>
        {auth.user ? (
          <Link href="/logout" method="delete">Logout</Link>
        ) : (
          <Link href="/login">Login</Link>
        )}
      </nav>

      {flash.success && <div className="alert-success">{flash.success}</div>}

      <main>{children}</main>
    </div>
  )
}

// Assign layout to page
Index.layout = page => <AppLayout>{page}</AppLayout>

File Upload

import { useForm } from '@inertiajs/react'

const { data, setData, post, progress } = useForm({
  avatar: null
})

<input
  type="file"
  => setData('avatar', e.target.files[0])}
/>

{progress && <progress value={progress.percentage} max="100" />}

<button => post('/profile/avatar', { forceFormData: true })}>
  Upload
</button>

Best Practices

DO

• Use <Link> instead of <a> tags
• Share common data via config (auth, flash)
• Validate on server - client is UX only
• Show loading states with processing
• Use layouts for consistent navigation

DON'T

• Don't use window.location - breaks SPA
• Don't create REST APIs - Inertia doesn't need them
• Don't fetch data client-side - server provides props
• Don't bypass Inertia router - breaks behavior

Detailed References

For framework-specific patterns:

• references/react-patterns.md - React hooks, TypeScript, advanced patterns
• references/vue-patterns.md - Vue 3 Composition API patterns
• references/svelte-patterns.md - Svelte stores and reactivity patterns