react-native-size

import Sizer from "./sizer";
 
const styles = StyleSheet.create({
  container: {
    flex: 1,
  },
});
class SizeTheThing extends Component {
  onUpdate = (prevMeasure, updatedMeasure) => {
    // Do stuff like animations
  }
  render() {
    return (
      <Sizer style={styles.container} onUpdate={this.onUpdate}>
        {({ measured, x, y, width, height }) => {
          return (
            <View>
              <Text>{measured ? "Yep" : "Nope"}</Text>
              <Text>{width} x {height}</Text>
              <Text>x:{x}, y:{y}</Text>
            </View>
          );
        }}
      </Sizer>
    );
  }
}

You can continue to use onLayout if necessary and it will receive the original event.

Additionally you can provide an onUpdate function that is called after the measurement has taken place and a re-render has ocurred. It receives the previous measurement, as well as the new measurement. This is a great spot to trigger animations.

The responsive prop defaults to true. When true if the container size changes the component will re-render. Set responsive={false} to disable and only measure the first time.