Adding Actions

Actions are the entry point into your data layer. Create a separate action for each use case and invoke it from your framework (Pages/Layouts in Next.js, loaders in SvelteKit, routes in Express, etc).

Creating an Action

Actions extend from Vla.Action and implement a handle() method:

import { Vla } from 'vla'

class ShowUserProfile extends Vla.Action {
  async handle(params) {
    const { id } = validateParams(params)
    const db = new Database()
    const user = await db.users.find({ id })

    return {
      name: user.name,
      email: user.email,
      joinedAt: user.createdAt
    }
  }
}

Invoke actions from your framework:

// Express
app.get('/users/:id', async (req, res) => {
  const profile = await ShowUserProfile.invoke(req.params)
  res.json(profile)
})

// Next.js
export default async function ProfilePage({ params }) {
  const profile = await ShowUserProfile.invoke(params)
  return <div>{profile.name}</div>
}

// SvelteKit
export const load = async ({ params }) => {
  return {
    profile: await ShowUserProfile.invoke(params)
  }
}

In the next guides, we’ll refactor this example to use services and repos for better structure and reusability.

HTTP Awareness with Context

Actions are usually HTTP-aware. Use Context to access request data:

const AppContext = Vla.createContext<{
  req: Request
  res: Response
}>()

class RenderProfileView extends Vla.Action {
  ctx = this.inject(AppContext)

  async handle(userId: string) {
    const db = new Database()
    const user = await db.users.find({ id: userId })

    this.ctx.res.render('profile', { user, isAdmin })
  }
}

Key Characteristics

• Actions aren’t meant to be reusable. There’s usually just one place that invokes a specific action
• Actions should return data optimized for their use case (e.g., the frontend). The frontend shouldn’t need to process data further
• Actions should not invoke other actions
• Actions can directly query the database, though using repos or services is recommended for better structure

Next Steps

To reuse business logic across actions, use Services.