React & Typescript, styled components & children

Question

I've tried so many different combinations to get this to work, but it's not applying the styles I've written for the StyledLines component, by them selves they work fine! Using the StyledLines component as a child, it doesn't work. The Target component styles work as expected.

import React, { Fragment, FunctionComponent } from 'react';
import styled from '@emotion/styled';


interface Crosshair {
  size: number;
  thickness: number;
}


const Target = styled.div<Crosshair>`
  position:absolute;
  &:before {
    content: '';
    display:block;
    position:absolute;
    top:50%;
    left:50%;
    background-color:transparent;
    border-color:#2fd5d5;
    margin-left:-${({size}) => size / 4}px;
    margin-top:-${({thickness}) => thickness / 4}px;
    width:${({size}) => size / 2}px;
    height:${({thickness}) => thickness / 2}px;
  }
`;

const Lines: FunctionComponent = ({children}) => <div className="line">{children}</div>;

const StyledLines = styled(Lines)<Crosshair>`
  position:absolute;
  &:nth-of-type(1) {
    top:0;
    left:0;
  }
  &:nth-of-type(2) {
    top:0;
    right:0;
  }
  &:nth-of-type(3) {
    bottom:0;
    right:0;
  }
  &:nth-of-type(4) {
    bottom:0;
    left:0;
  }
  &:after, &:before {
    content: '';
    display:block;
    position:absolute;
    top:50%;
    left:50%;
    background:#2fd5d5;
    margin-left:-${({size = 2}) => size / 2}px;
    margin-top:-${({thickness = 24}) => thickness / 2}px;
    width:${({size = 2}) => size}px;
    height:${({thickness = 24}) => thickness}px;
  }
  &:before {
    transform: rotateZ(90deg);
  }
`;


export default function Crosshairs() {
  return <Fragment>
    <div>
      {[0,1,2,3].map(i => <StyledLines key={i} size={24} thickness={2}>
        <Target size={24} thickness={2} />
      </StyledLines>)}
    </div>
  </Fragment>;
}

Answer 1

Lines是一个普通的 React 组件，而不是一个样式化的组件，因此您必须将className传递给要设置样式的 DOM 部分：

const Lines: FunctionComponent = ({children, className}) => <div className={`line ${className}`}>{children}</div>;