The migration:check command exits with ERR_IMPORT_ASSERTION_TYPE_MISSING

[piotr-cz]

Describe the bug

Affects only 6.2.2, both Windows and Linux
Affects only commands and only related to snapshots (not programmatic usage)

It looks like that in 7e8409b the support to require json files have been removed together with a jest workaround.

Partially reverting commit fixes the issue

static async dynamicImport(id) {
    if (id.endsWith('.json')) {
        return require(id);
    }

    //...
}

Context

The dynamicImport method by default uses config's

mikro-orm/packages/core/src/utils/Configuration.ts

Line 154 in ff3148b

dynamicImportProvider: /* istanbul ignore next */ (id: string) => import(id),

which produces the error.

Node's dynamic import() for json files should be used along with

• Import attributes in node >= 18.20

  import(id, { with: { type: 'json' } })

• Import assertions in node < 18.20

  import(id, { assert: { type: 'json' } })

Another thing is that the json file is imported in the default namespace.

As as result, such fix is possible:

async dynamicImportProvider(id) {
  if (id.endsWith('.json')) {
    const { default: data } = await import(id, { assert: { type: 'json' }, with: { type: 'json' } })

    return data
  }

  return import(id)
}

Reproduction

Prepare project as in docs > Creating a new project

Execute

npx mikro-orm-esm migration:check

See output

Check if migrations are needed. Useful for bash scripts.
...

TypeError [ERR_IMPORT_ASSERTION_TYPE_MISSING]: Module "file:///xxx/src/migrations/.snapshot.json" needs an import assertion of type "json"
    at new NodeError (node:internal/errors:405:5)
    at validateAssertions (node:internal/modules/esm/assert:95:15)
    at defaultLoad (node:internal/modules/esm/load:91:3)
    at nextLoad (node:internal/modules/esm/loader:163:28)
    at xxx\node_modules\ts-node\src\esm.ts:255:45
    at async addShortCircuitFlag (xxx\node_modules\ts-node\src\esm.ts:409:15)
    at async nextLoad (node:internal/modules/esm/loader:163:22)
    at async ESMLoader.load (node:internal/modules/esm/loader:603:20)
    at async ESMLoader.moduleProvider (node:internal/modules/esm/loader:457:11)
    at async link (node:internal/modules/esm/module_job:68:21) {
  code: 'ERR_IMPORT_ASSERTION_TYPE_MISSING'
}

What driver are you using?

@mikro-orm/sqlite

MikroORM version

6.2.2

Node.js version

18.18.2

Operating system

Windows

Validations

• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Slack.
• The provided reproduction is a minimal reproducible example of the bug.

[B4nan]

I knew this would break at least something. Good old require, I miss you.

[B4nan]

I think I will just replace the import call with a simple readJSONSync from fs-extra.

[piotr-cz]

Yes, the readFileSync is probably best fit for this case