koala73/worldmonitor · error · Error

Invalid format: expected an object with a data property.

Error message

Invalid format: expected an object with a data property.

What it means

UI error in importSettings: the settings file parsed as JSON but its shape is wrong — there is no usable object 'data' property (missing, non-object, or an array). A shape guard distinguishing valid exports from arbitrary JSON before version migration runs.

Source

Thrown at src/utils/settings-persistence.ts:88

  URL.revokeObjectURL(url);
}

export function importSettings(file: File): Promise<ImportResult> {
  return new Promise((resolve, reject) => {
    if (file.size > MAX_IMPORT_SIZE_BYTES) {
      reject(new Error('File is too large. Maximum size is 5MB.'));
      return;
    }

    const reader = new FileReader();

    reader.onload = (e) => {
      try {
        const result = e.target?.result as string;
        const parsed = JSON.parse(result) as ExportedSettings;

        if (!parsed || typeof parsed.data !== 'object' || Array.isArray(parsed.data)) {
          throw new Error('Invalid format: expected an object with a data property.');
        }

        if (parsed.version !== 1) {
          throw new Error(`Unsupported settings version: ${parsed.version}`);
        }

        let keysImported = 0;
        const importedKeys: string[] = [];
        for (const [key, value] of Object.entries(parsed.data)) {
          if (isSettingsKey(key) && typeof value === 'string') {
            localStorage.setItem(key, value);
            keysImported++;
            importedKeys.push(key);
          }
        }
        invalidatePanelStorageCacheForKeys(importedKeys);

        resolve({ success: true, keysImported });

View on GitHub (pinned to a96956387a)

Solutions

1. Use a file produced by the app's exportSettings function
2. Verify the JSON has a top-level 'data' object plus 'version'

When it happens

Trigger: Thrown at src/utils/settings-persistence.ts:85 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of koala73/worldmonitor@a96956387a (2026-08-21). Data as JSON: /api/errors/734f0b5907f992ec. Report an issue: GitHub.