Elysia Fault

You can add error middleware to APIs made with Elysia.

Instalation

  bun add elysia-fault

Usage

It is important to remember that as it is an error handling middleware, it must be used before controllers or anything that will need to have error handling

Standard usage

import { elysiaFault, Errors } from 'elysia-fault'
import Elysia from 'elysia'

const app = new Elysia()
    .use(elysiaFault())
    .get('/', () => {
        throw new Errors.BadRequest('Example for Bad Request Error')
    })
    .listen(3333)

console.log(`Server is running at ${app.server?.hostname}:${app.server?.port}`)

Output of standard usage with status code 400

{
    "name": "BadRequest",
    "message": "Example for Bad Request Error"
}

The middleware changes the NotFound and Validation standard errors

import { elysiaFault } from 'elysia-fault'
import Elysia from 'elysia'

const app = new Elysia()
    .use(elysiaFault())
    .get('/', () => 'Hello World')
    .listen(3333)

console.log(`Server is running at ${app.server?.hostname}:${app.server?.port}`)

This will be the 404 error that your app will return by default when attempting a request using the http://localhost:3333/notfound route in the GET method

{
    "message": "GET http://localhost/notfound is not a valid endpoint."
}

But if you don't like the new default error, you can customize it

import { elysiaFault } from 'elysia-fault'
import Elysia from 'elysia'

const app = new Elysia()
    .use(elysiaFault({
        found: (err) => `My custom error on ${err.url} with method ${err.method}`
    }))
    .get('/', () => 'Hello World')
    .listen(3333)

console.log(`Server is running at ${app.server?.hostname}:${app.server?.port}`)

With this modified error, we just told it to return a string, so it will still do it with the status code 404

"My custom error on http://localhost/notfound with method GET"

But if you like json, you can also ask it to return an object

import { elysiaFault } from 'elysia-fault'
import Elysia from 'elysia'

const app = new Elysia()
    .use(elysiaFault({
        found: (err) => ({ message: `My custom error with an object` })
    }))
    .get('/', () => 'Hello World')
    .listen(3333)

console.log(`Server is running at ${app.server?.hostname}:${app.server?.port}`)

So it returns this error in a not found error

{
    "message": "My custom error with an object"
}

But if you still think you need more customization, you can create your own errors with these class extensions

import { elysiaFault, Errors } from 'elysia-fault'
import Elysia from 'elysia'

class MyCustomError extends Errors.ApiError {
    constructor(message: string) {
        super(message, 500, 'MyCustomError')
        //super(error message, status code, error name)
    }
}

const app = new Elysia()
    .use(elysiaFault())
    .get('/', () => {
        throw new MyCustomError('Custom error made by myself')
    })
    .listen(3333)

console.log(`Server is running at ${app.server?.hostname}:${app.server?.port}`)

Custom error output

{
    "name": "MyCustomError",
    "message": "Custom error made by myself"
}

But if you still don't like how these custom errors are returning, you can still customize the format of these errors as well.

import { elysiaFault, Errors } from 'elysia-fault'
import Elysia from 'elysia'

const app = new Elysia()
    .use(elysiaFault({
        config: (err) => err.message
    }))
    .get('/', () => {
        throw new Errors.BadRequest('Example for Bad Request Error with only text')
    })
    .listen(3333)

console.log(`Server is running at ${app.server?.hostname}:${app.server?.port}`)

Output of standard usage with status code 400

"Example for Bad Request Error with only text"