Migration Guide

Migrate your existing applications from Elysia, Hono, or Fastify to AsiJS.

Automatic Migration (Codemod)

AsiJS includes a built-in codemod CLI for automatic migration:

# Preview changes (dry run)
bunx asijs migrate ./src --dry-run -v

# Migrate from Elysia
bunx asijs migrate ./src --from elysia

# Migrate from Hono
bunx asijs migrate ./src --from hono

# Migrate from Fastify
bunx asijs migrate ./app.ts --from fastify

The codemod handles 60+ patterns: imports, route definitions, plugins, middleware, and more.

Manual Migration

Elysia → AsiJS

Elysia	AsiJS
new Elysia()	new Asi()
.get() / .post()	app.get() / app.post()
.use(plugin)	app.plugin(plugin)
.derive(fn)	app.before(fn)
.guard()	app.group() with middleware
t.String / t.Number	Type.String / Type.Number
set.status	ctx.status(N)
@elysiajs/cors	import { cors } from "asijs"

Hono → AsiJS

Hono	AsiJS
new Hono()	new Asi()
c.text(str)	return str
c.json(obj)	return obj
c.html(str)	ctx.html(str)
c.req.param("name")	ctx.params.name
c.req.query("q")	ctx.query.q
c.status(N)	ctx.status(N)
hono/cors → cors	import { cors } from "asijs"
export default app	app.listen()

Fastify → AsiJS

Fastify	AsiJS
fastify()	new Asi()
reply.code(N)	ctx.status(N)
reply.send(data)	return data
request.params	ctx.params
request.query	ctx.query
app.register(plugin)	app.plugin(plugin)
app.listen({ port })	app.listen(port)
request.log.info()	console.log()

Note: The codemod is a best-effort regex-based transformation. Complex cases (nested routes, custom plugins) may require manual adjustments.