[Home](./index.md) > [@firebase/firestore](./firestore.md) > [/](./firestore_.md) > [SetOptions](./firestore_.setoptions.md) ## SetOptions type An options object that configures the behavior of [setDoc()](./firestore_lite.setdoc.md), and calls. These calls can be configured to perform granular merges instead of overwriting the target documents in their entirety by providing a `SetOptions` with `merge: true`. Signature: ```typescript export declare type SetOptions = { readonly merge?: boolean; } | { readonly mergeFields?: Array; }; ``` References: [FieldPath](./firestore_.fieldpath.md)