Passing props into external stylesheet in React Native?

I rather to have my styles in a separate file styles.js.
Inside styles.js:

export const styles = (props) => StyleSheet.create({
        icon : {
        color: props.iconColor,
        fontSize: props.iconSize
      }
    }

Inside your main class you can pass the value

return (
    <Icon style={styles(this.props).icon} />
  );

Alternatively you can those value directly
so it would be

export const styles = (iconColor,iconSize) => StyleSheet.create({
    icon : {
    color: iconColor,
    fontSize: iconSize
  }
}

and inside your main class

return (
    <Icon style={styles(this.props,iconColor, 
this.props.iconSize).icon} />
 );