flow

Container.js

//@flow
import type { ComponentType } from 'react';
import React from 'react';
import styled from 'styled-components';

type Align = 'flex-start' | 'flex-end' | 'center';
type Props = {
  align?: Align;
}

export const Container: ComponentType<Props> = styled.View`
  flex: 1;
  align-items: ${({align = 'center'}) => align};
  justify-content: center;
  background-color: #fff;
`;

Landing.js

//@flow
import React, { Component } from 'react';
import { Text } from 'react-native';
import { Container } from '../components';

export default class Landing extends Component<{}> {
  render() {
    return (
      <Container>
        <Text testID={`landing-text`}>{`Landing`}</Text>
      </Container>
    );
  }
}