pubkey/rxdb · error · RxError

DOC4

DOC4

Error message

RxDB Error-Code: DOC4. 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

DOC4 is thrown by RxDocument.get$()/get() when the given object path is not defined in the collection's RxSchema. RxDB validates the path against the JSON schema before creating an observable, so a typo or a path outside the schema fails fast instead of emitting undefined. It guards against silently observing a field that can never exist.

Source

Thrown at src/rx-document.ts:161

            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(
                map((data: any) => getProperty(data, path)),
                distinctUntilChanged((prev: any, curr: any) => {
                    /**
                     * Use deepEqual for non-primitive values (objects/arrays)
                     * because the default === comparison always fails across
                     * document revisions since each revision creates new object references.
                     */
                    return deepEqual(prev, curr);
                })
            );
    },

View on GitHub (pinned to af6fb65f94)

Solutions

Fix the path string so it matches a path defined in the collection's JSON schema
Verify with collection.schema.jsonSchema (or getSchemaByObjectPath) that the path exists
Enable the dev-mode plugin during development to get the full message including the offending path

Example fix

// before
doc.get$('nam.last'); // DOC4: path not in schema
// after
doc.get$('name.last'); // path exists in the schema

Defensive patterns

Strategy: validation

Validate before calling

import { getSchemaByObjectPath } from 'rxdb/plugins/schema-helper';
function pathExists(doc: RxDocument, path: string): boolean {
  return !!getSchemaByObjectPath(doc.collection.schema.jsonSchema, path);
}
if (!pathExists(doc, 'name.last')) throw new Error('unknown schema path');

Type guard

function hasSchemaPath(doc: RxDocument, path: string): path is string {
  return !!getSchemaByObjectPath(doc.collection.schema.jsonSchema, path);
}

Try / catch

try {
  doc.get$(path).subscribe(render);
} catch (err) {
  if ((err as any).code === 'DOC4') console.warn('bad path', path);
}

Prevention

Derive paths from constants or the schema itself instead of string literals
Run with the dev-mode plugin in development to get full messages
Add tests that assert schema paths used by UI code exist
Review schema migrations for renamed fields and update all path usages

When it happens

Trigger: Calling doc.get$('name.lastname') or doc.get('field.x') where 'name.lastname' (or any intermediate segment) is not declared in the collection schema; using dot-notation paths that reference nested properties not present in the JSON schema; observing a removed or renamed field after a schema change.

Common situations: Field renamed in schema but queries/observables still use the old name; assuming nested paths are allowed without declaring nested objects in the schema; forgetting to update secondary indexes or UI bindings after a schema migration.

Related errors

AI-assisted analysis of pubkey/rxdb@af6fb65f94 (2026-08-31). Data as JSON: /api/errors/48f67eae150a625c. Report an issue: GitHub.