import { ImageStyle, TextStyle, ViewStyle } from 'react-native';

type Style = ViewStyle | TextStyle | ImageStyle;
type NullableStyle = Style | null | undefined;

const isNil = (val: unknown) => val == null;

const merge = (obj1: NullableStyle, obj2: NullableStyle) =>
  obj2 == null
    ? obj1
    : Object.keys(obj2).reduce((res, key) => (isNil(obj2[key]) ? res : { ...res, [key]: obj2[key] }), obj1);

const composeStyles = (styles: NullableStyle[] = []): NullableStyle => styles.reduce(merge, {});
export default composeStyles;