Detect if shift key is down React Native

问题

How can I detect if the shift key is currently pressed down? I have a text input, and when the user presses the enter key I only want to submit the form if they are not currently pressing the enter key (same form functionality as Facebook Messenger on desktop).

Here is my text input:

<TextInput
    style={styles.input}
    placeholder={'Enter message'}
    onKeyPress={this.handleKeyPress}
/>

And here is the handler:

handleMessageInputKeyPress(e) {
    if(e.nativeEvent.key == "Enter"){
        // Now check if the SHIFT key is currently pressed or not...
    }
}

来源：https://stackoverflow.com/questions/41648156/detect-if-shift-key-is-down-react-native