End-to-End Type Safety

Imagine you have a toy train set.

Each piece of the train track has to fit perfectly with the next one, like puzzle pieces.

End-to-end type safety is like making sure all the pieces of the track match up correctly so the train doesn't fall off or get stuck.

For a framework to have end-to-end type safety means you can connect client and server in a type-safe manner.

Elysia provide end-to-end type safety without code generation out of the box with RPC-like connector, Eden

Others framework that support e2e type safety:

tRPC
Remix
SvelteKit
Nuxt
TS-Rest

Elysia allows you to change the type on the server and it will be instantly reflected on the client, helping with auto-completion and type-enforcement.

Eden

Eden is a RPC-like client to connect Elysia end-to-end type safety using only TypeScript's type inference instead of code generation.

Allowing you to sync client and server types effortlessly, weighing less than 2KB.

Eden is consists of 2 modules:

Eden Treaty (recommended): an improved version RFC version of Eden Treaty
Eden Fetch: Fetch-like client with type safety.

Below is an overview, use-case and comparison for each module.

Eden Treaty (Recommended)

Eden Treaty is an object-like representation of an Elysia server providing end-to-end type safety and a significantly improved developer experience.

With Eden Treaty we can connect interact Elysia server with full-type support and auto-completion, error handling with type narrowing, and creating type safe unit test.

Example usage of Eden Treaty:

typescript

import { treaty
 } from '@elysiajs/eden'
import type { App
 } from './server'

const app
 = treaty
<App
>('localhost:3000')

app
.





// Call [GET] at '/'
const { data } = await app
.index
.get
()

// Call [PUT] at '/nendoroid/:id'
const { data
: nendoroid
, error
 } = await app
.nendoroid
({ id
: 1895 }).put
({
    name
: 'Skadi',
    from
: 'Arknights'
})

Eden Fetch

A fetch-like alternative to Eden Treaty for developers that prefers fetch syntax.

typescript

import { edenFetch } from '@elysiajs/eden'
import type { App } from './server'

const fetch = edenFetch<App>('http://localhost:3000')

const { data } = await fetch('/name/:name', {
    method: 'POST',
    params: {
        name: 'Saori'
    },
    body: {
        branch: 'Arius',
        type: 'Striker'
    }
})