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# guide/gs/reactNative/addAPI4

The actual implementation will depend on the actual functionality.

### Finishing steps

#### 1. Push the code and integrate the updated source

Now `npm install` your forked version to your application.

The new functionality is now ready to use.

#### 2. Access the new functionality

The app can now access the new API as follows:

```js
onDocumentLoaded = () => {
    this._viewer.getField('someFieldName').then((field) => {
        if (field !== undefined) {
            console.log('field name:', field.fieldName);
            console.log('field value:', field.fieldValue);
            console.log('field type:', field.fieldType);
        }
    });
}

onLayoutChanged = () => {
    console.log("Layout changed");
}

<DocumentView
    ref={(c) => this._viewer = c}
    pageChangeOnTap={false}
    onDocumentLoaded={this.onDocumentLoaded}
    onLayoutChanged={this.onLayoutChanged}
    document={this.state.document}
/>
```


---

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