[Home](./index.md) > [@firebase/firestore](./firestore.md) > [lite](./firestore_lite.md) > [Settings](./firestore_lite.settings.md) > [ignoreUndefinedProperties](./firestore_lite.settings.ignoreundefinedproperties.md) ## Settings.ignoreUndefinedProperties property Whether to skip nested properties that are set to `undefined` during object serialization. If set to `true`, these properties are skipped and not written to Firestore. If set to `false` or omitted, the SDK throws an exception when it encounters properties of type `undefined`. Signature: ```typescript ignoreUndefinedProperties?: boolean; ```