Document engine error codes

Every failure is a DocumentEngineError with a stable code. Document engine error codes never change within 1.x, so switch on the code and never on the message text.

import { isDocumentEngineError } from "fabricjs-document-engine";
 
try {
  await engine.load(id);
} catch (error) {
  if (isDocumentEngineError(error) && error.code === "UNSAVED_CHANGES") {
    await engine.save();
    await engine.load(id);
  }
}

Besides code, an error can carry issues, unknownTypes, missingAssets, missingFonts, problems, migrationFrom, retryable and cause.

All document engine error codes

Code	When
`INVALID_DOCUMENT`	The document shape is wrong, or the imported text is not JSON
`UNSAFE_DOCUMENT`	An unsafe image address, too many objects, or nesting too deep
`UNSUPPORTED_SCHEMA`	Written by a newer major version of this package
`UNKNOWN_OBJECT_TYPE`	A custom class is not registered
`INVALID_CUSTOM_OBJECT`	A registered class has no static `type`, or is not a Fabric.js class
`MIGRATION_FAILED`	An older document could not be upgraded
`LOAD_ABORTED`	A newer load, or `destroy`, stopped this load
`LOAD_FAILED`	Fabric.js or storage failed to load
`MISSING_ASSETS`	Images could not be loaded
`MISSING_FONTS`	Fonts are unavailable and `requireFonts` is on
`ASSET_UPLOAD_FAILED`	The `upload` handler failed
`UNSAVED_CHANGES`	Opening another document would discard unsaved changes
`STORAGE_MISSING`	`load`, `save` or autosave was used without storage
`SAVE_FAILED`	Storage refused after all retries
`SAVE_CONFLICT`	Another tab or device saved first
`SAVE_CANCELLED`	A save was dropped because another document was opened, or the engine was destroyed
`DOCUMENT_NOT_FOUND`	A built-in adapter has no such document
`HISTORY_FAILED`	Undo or redo could not rebuild an object
`RECOVERY_MISSING`	Recovery is not configured
`RECOVERY_NOT_FOUND`	There is no recovery copy
`RECOVERY_FAILED`	A recovery copy could not be written
`VERSIONS_UNSUPPORTED`	Storage has no version methods
`VERSION_NOT_FOUND`	There is no such version
`VERSION_FAILED`	An automatic version failed
`INVALID_EXPORT_OPTIONS`	The export options are not valid
`EXPORT_BLOCKED`	An image or font would break the export. See `error.problems`
`EXPORT_ABORTED`	The export was cancelled
`EXPORT_FAILED`	Rendering failed
`ENGINE_DESTROYED`	The engine was used after `destroy()`

The ones that need UI

Most document engine error codes are logged and forgotten. These need the user to decide, so give them a dialog: SAVE_CONFLICT (save conflicts), MISSING_ASSETS (images and fonts) and UNSAVED_CHANGES. A full handler is in the production checklist.

Error codes

All document engine error codes

The ones that need UI