Doubts about using with mswjs/data

[Mauro Accornero]

Hello,

I'm trying to use mswjs/data with mswjs/http-middleware with this code:

db.js

import { faker } from '@faker-js/faker'
import { factory, primaryKey, oneOf } from '@mswjs/data'

faker.seed(123)

function createItem(db) {
    return db.book.create({
        author: db.author.create(),
    })
}

const db = factory({
    book: {
        id: primaryKey(() => faker.datatype.uuid()),
        title: faker.lorem.text,
        year: faker.date.past().getFullYear(),
        author: oneOf('author')
    },
    author: {
        id: primaryKey(() => faker.datatype.uuid()),
        name: faker.name.fullName,
    },
})

for(let k = 0; k < 100; k++){
    createItem(db)
}

export default db

server.js

import express from 'express'
import { createMiddleware } from '@mswjs/http-middleware'
import db from "./db.js";

const app = express()

app.use(express.json())

app.use(createMiddleware(...db.book.toHandlers('rest'), ...db.author.toHandlers('rest')))

app.use((_req, res) => {
    res.status(404).send({ error: 'Mock not found' })
})

app.listen(process.argv[2],() => {
    console.log(`Mock server started on port ${process.argv[2]}`)
})

I start the server with

node ./server.js 9090

almost everything works fine but when I try to create a new book with a POST to localhost:9090/books and a JSON payload like:

{
    "title": "asdasdas",
    "year": 2013,
    "author": {
        "id": "b463b8bb-76cf-46a9-b266-5ab5730b69ba",
        "name": "Ms. Bessie Daniel"
    }
}

I get a 500 status code with this message:

{"message":"Failed to resolve a \"ONE_OF\" relationship to \"author\" at \"book.author\" (id: \"861737c5-7ecd-40a8-be99-634b46bad09a\"): expected a referenced entity to be \"author\" but got {\"id\":\"b463b8bb-76cf-46a9-b266-5ab5730b69ba\",\"name\":\"Ms. Bessie Daniel\"}"}

I verified that the author was correct and if I try to create a book without the author, the book it's correctly saved.

I tried different payloads with Postman, but without luck.

I'm using

    "msw": "^0.47.4",
    "@mswjs/data": "^0.10.2",
    "@mswjs/http-middleware": "^0.5.2",

with node v16.14.0

probably I'm missing something, any suggestion it's welcome.

update: Looks like the error comes from msw/data https://github.com/mswjs/data/blob/main/src/relations/Relation.ts#L172

[Artem Zakharchenko]

Hey, @mauroaccornero. I'm sorry to hear you're having trouble making http-middleware and data work together. Do you happen to have your project published on GitHub? If you create a reproduction repository/sandbox I can help you look into the issue.

[Mauro Accornero]

Hi @kettanaito, here is a little repository with a test to replicate the issue https://github.com/mauroaccornero/mswjs-test.

Looks like db.book.create() only accepts references for a related entity, it's possible to get the same error with:

db.book.create({
    "title": "asdasdas",
    "year": 2013,
    "author": {
        "id": "b463b8bb-76cf-46a9-b266-5ab5730b69ba",
        "name": "Ms. Bessie Daniel"
    }
})

while it works with a reference

const author = db.author.create()
db.book.create({author})

Let me know if I can do something to help and thanks for your support!