voluptasmollitia/docs-exp/firestore_.updatedoc.md

Monorepo for the Firebase JavaScript SDK

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[Home](./index.md) &gt; [@firebase/firestore](./firestore.md) &gt; [/](./firestore_.md) &gt; [updateDoc](./firestore_.updatedoc.md)

## updateDoc() function

Updates fields in the document referred to by the specified `DocumentReference`<!-- -->. The update will fail if applied to a document that does not exist.

<b>Signature:</b>

```typescript
export declare function updateDoc(reference: DocumentReference<unknown>, data: UpdateData): Promise<void>;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  reference | [DocumentReference](./firestore_.documentreference.md)<!-- -->&lt;unknown&gt; | A reference to the document to update. |
|  data | [UpdateData](./firestore_.updatedata.md) | An object containing the fields and values with which to update the document. Fields can contain dots to reference nested fields within the document. |

<b>Returns:</b>

Promise&lt;void&gt;

A Promise resolved once the data has been successfully written to the backend (note that it won't resolve while you're offline).