pubkey/rxdb · error · RxError

DOC3

DOC3

Error message

RxDB Error-Code: DOC3. Hint: Error messages are not included in RxDB core to reduce build size. To show the full error messages and to ensure that you do not make any mistakes when using RxDB, use the dev-mode plugin when you are in development mode: https://rxdb.info/dev-mode.html?console=error

What it means

DOC3 is thrown when you try to observe a final (read-only) schema field via RxDocument.get$(path). Final fields cannot be modified, so their value can never change and an observable would never emit anything new; RxDB rejects the call to surface the mistake. This check only runs in dev mode.

Source

Thrown at src/rx-document.ts:150

    /**
     * returns observable of the value of the given path
     */
    get$(this: RxDocument, path: string): Observable<any> {
        if (overwritable.isDevMode()) {
            if (path.includes('.item.')) {
                throw newRxError('DOC1', {
                    path
                });
            }

            if (path === this.primaryPath) {
                throw newRxError('DOC2');
            }

            // final fields cannot be modified and so also not observed
            if (this.collection.schema.finalFields.includes(path)) {
                throw newRxError('DOC3', {
                    path
                });
            }

            const schemaObj = getSchemaByObjectPath(
                this.collection.schema.jsonSchema,
                path
            );

            if (!schemaObj) {
                throw newRxError('DOC4', {
                    path
                });
            }
        }

        return this.$
            .pipe(

View on GitHub (pinned to af6fb65f94)

Solutions

1. Read the final field statically: const createdAt = doc.get('createdAt').
2. Exclude final fields (this.collection.schema.finalFields) from any dynamic observation logic.
3. If the value must change, remove final: true from the schema (requires a schema/migration rethink, not a code-only fix).

Example fix

// before
doc.get$('createdAt').subscribe(v => ...);
// after
const createdAt = doc.get('createdAt'); // final fields never change, no observation needed

function assertNotFinal(doc, path) {
  if (doc.collection.schema.finalFields.includes(path)) {
    throw new Error('Final field cannot be observed, read statically: ' + path);
  }
}

function isMutableField(doc, path) {
  return !doc.collection.schema.finalFields.includes(path);
}

try {
  obs = doc.get$(path);
} catch (err) {
  if (String(err?.code) === 'DOC3') {
    // final fields never change: emit the static value once
    import('rxjs').then(({ of }) => obs = of(doc.get(path)));
  } else {
    throw err;
  }
}

When it happens

Trigger: Calling doc.get$() on a field defined with final: true in the RxJsonSchema, e.g. a createdAt timestamp, while the dev-mode plugin is active.

Common situations: Observing schema-internal fields like createdAt/updatedAt marked final; generic observation helpers that walk all schema properties including final ones; migrating schemas where a field newly became final.

Related errors

• DOC1
• DOC2
• DOC9
• DB9
• DOC4

AI-assisted analysis of pubkey/rxdb@af6fb65f94 (2026-08-31). Data as JSON: /api/errors/87f330c6e6f70d15. Report an issue: GitHub.