Trigger onProperty of component - reactjs

Question

I have tried to trigger (refer, call, correct terminology?) an onScale from the property of this component from the react-native-photo-view API:
<PhotoView
source={{ uri: }}
onLoad={() => console.log('onLoad called')}
onTap={(event) =>
console.log(`onTap called: ${event.nativeEvent.x}${event.nativeEvent.y}`)}
onScale={() => console.log('onScale called')}
minimumZoomScale={1}
maximumZoomScale={3}
scale={0.5}
resizeMode={'contain'}
androidScaleType={'fitXY'}
style={styles.photo}
/>
How could i "trigger" this onScale={} property from lets say a <Button onClick={triggerOnScale()} /> to zoom with the scale factor? Any direct code example or pointers to techniques/methods that could help would be greatly appreciated!

Answer 1

If onScale is a method of your PhotoView component then you can set up a reference to call it:
handleOnClick = () => this.photoView.onScale()
//just use the handleOnClick wherever you want your click and it will call onScale also
<PhotoView
source={{ uri: }}
onLoad={() => console.log('onLoad called')}
onTap={(event) =>
console.log(`onTap called: ${event.nativeEvent.x}${event.nativeEvent.y}`)}
**ref={(photoView) => this.photoView = photoView}**
minimumZoomScale={1}
maximumZoomScale={3}
scale={0.5}
resizeMode={'contain'}
androidScaleType={'fitXY'}
style={styles.photo}
/>

Answer 2

If you want your onScale handler and your button's onClick handler to fire the same function, then you can just bind a function to the containing component and then pass the function's reference to the Button and PhotoView respectively.
class YourComponent extends Component {
constructor(props){
super(props);
this.someFunction = this.someFunction.bind(this);
}
someFunction() {
console.log('Inside some Function.);
}
render() {
return(
<div>
<PhotoView onScale={this.someFunction} />
<Button onClick={this.someFunction} />
</div>
);
}
}