Response

Once fetch method is called, Eden Treaty return an Promise with object as follows:

data - returned value of the response (2xx)
error - returned value from the response (>= 3xx)
response Response - Web Standard Response class
status number - HTTP status code
headers FetchRequestInit['headers'] - response's headers

Once returned, you must provide an error handling to ensure that value is truly returned to access the value, otherwise the value will be nullable.

typescript

import { Elysia
, t
 } from 'elysia'
import { treaty
 } from '@elysiajs/eden'

const app
 = new Elysia
()
    .post
('/user', ({ body
: { name
 }, error
 }) => {
        if(name
 === 'Otto')
            return error
(400, 'Bad Request')

        return name

    }, {
        body
: t
.Object
({
            name
: t
.String
()
        })
    })
    .listen
(3000)

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

const submit
 = async (name
: string) => {
    const { data
, error
 } = await api
.user
.post
({
        name

    })

    // type: string | null
    console
.log
(data
)

    if(error
)
        switch(error
.status
) {
            case 400:
                // Error type will be narrow down
                throw error
.value


            default:
                throw error
.value

        }

    // Once error is handle, type will be unwrapped
    // type: string
    return data

}

By default, Elysia will infers error and response type to TypeScript automatically, and Eden will be providing an auto-completion and type narrowing for accurate behavior.

TIP

If server response with HTTP status >= 300, then value will be always be null, and error will have a returned value instead.

Otherwise, response will be passed to data.

Response ​

Response