Sentinel values that can be used when writing document fields with `set()` or `update()`.

**Signature:**

    export declare abstract class FieldValue 

## Methods

| Method | Modifiers | Description |
|---|---|---|
| [isEqual(other)](https://firebase.google.com/docs/reference/js/firestore_lite.fieldvalue#fieldvalueisequal) |   | Compares `FieldValue`s for equality. |

## FieldValue.isEqual()

Compares `FieldValue`s for equality.

**Signature:**

    abstract isEqual(other: FieldValue): boolean;

#### Parameters

| Parameter | Type | Description |
|---|---|---|
| other | [FieldValue](https://firebase.google.com/docs/reference/js/firestore_lite.fieldvalue#fieldvalue_class) |   |

**Returns:**

boolean