Set width and height to React-native modal

According to the Modal documentation, there is no style prop to be set.

You can try setting the <View> dimensions inside the <Modal> instead:

<Modal transparent={true}
       visible={this.state.isVisible}
       onRequestClose={this.closeModal}>
  <View style={{
          flex: 1,
          flexDirection: 'column',
          justifyContent: 'center',
          alignItems: 'center'}}>
    <View style={{
            width: 300,
            height: 300}}>
      ...
    </View>
  </View>
</Modal>