[Home](./index.md) > [@firebase/firestore](./firestore.md) > [/](./firestore_.md) > [FieldValue](./firestore_.fieldvalue.md) ## FieldValue class Sentinel values that can be used when writing document fields with `set()` or `update()`. Signature: ```typescript export declare abstract class FieldValue ``` ## Methods | Method | Modifiers | Description | | --- | --- | --- | | [isEqual(other)](./firestore_.fieldvalue.isequal.md) | | Compares FieldValues for equality. |