React Class 組件轉換為功能組件

Question

我有這段代碼，我需要將此代碼格式更改為功能組件。

我需要將這些樣式化組件添加到單獨的文件中，請幫我這樣做。

如果更好，您可以給我一個代碼沙箱示例。

（我嘗試這樣做，但我遇到了一些錯誤，比如這個問題，這就是我尋求幫助的原因

錯誤 - 錯誤：元素類型無效：需要一個字符串（對於內置組件）或一個類/函數（對於復合組件）但得到：未定義

這就是我尋求幫助的原因）

// Import styled-components library
const sc = styled.default
const { css } = styled

// Cache container
const container = document.querySelector('.container')

// Helper function to convert pixels to rems
const remy = px => `${px / 16}rem`

// Function for calculating value for width
const getWidth = (value) => {
  if (!value) return

  let width = value / 12 * 100
  return `width: ${width}%;`
}

// Function for calculating value for flex
const getFlex = (value) => {
  if (!value) return

  let flex = value / 12 * 100
  return `flex: 0 0 ${flex}%;`
}

const LayoutWrapper = sc.div`
  padding-top: 32px;
  padding-bottom: 32px;

  // Fix for applying proper box-sizing
  html:not(&) {
    box-sizing: border-box;

    *,
    *::before,
    *::after {
      box-sizing: inherit;
    }
  }

  body:not(&) {
    font: 16px / 1.618 Arial, Verdana, sans-serif;
  }
`

// Grid container
const GridContainer = sc.div`
  padding-right: ${remy(15)};
  padding-left: ${remy(15)};
  margin-right: auto;
  margin-left: auto;
  width: 100%;

  // Breakpoint for tablets
  @media (min-width: 576px) {
    max-width: ${remy(540)};
  }

  // Breakpoint for small desktops
  @media (min-width: 768px) {
    max-width: ${remy(720)};
  }

  // Breakpoint for medium desktops
  @media (min-width: 992px) {
    max-width: ${remy(9600)};
  }

  // Breakpoint for large desktops and HD devices
  @media (min-width: 1200px) {
    max-width: ${remy(1140)};
  }
`

// Grid row
const GridRow = sc.div`
  margin-right: ${remy(-15)};
  margin-left: ${remy(-15)};
  display: flex;
  flex-wrap: wrap;
`

// Grid columns
const GridColumn = sc.div`
  padding-right: ${remy(15)};
  padding-left: ${remy(15)};

  // Columns for mobile
  ${({ xs }) => (xs ? getFlex(xs) : 'flex: 0 0 100%')};
  ${({ xs }) => (xs ? getWidth(xs) : 'width: 100%')};

  // Columns for tablets
  @media (min-width: 576px) {
    ${({ sm }) => sm && getFlex(sm)};
    ${({ sm }) => sm && getWidth(sm)};
  }

  // Columns for small desktops
  @media (min-width: 768px) {
    ${({ md }) => md && getFlex(md)};
    ${({ md }) => md && getWidth(md)};
  }

  // Columns for medium desktops
  @media (min-width: 992px) {
    ${({ lg }) => lg && getFlex(lg)};
    ${({ lg }) => lg && getWidth(lg)};
  }

  // Columns for large desktops and HD devices
  @media (min-width: 1200px) {
    ${({ xl }) => xl && getFlex(xl)};
    ${({ xl }) => xl && getWidth(xl)};
  }
`

// Flipping card
const Card = sc.article`
  position: relative;
  width: 100%;
  min-height: ${remy(380)};
  cursor: pointer;
  perspective: 1000px;
  transition: all .25s ease-in-out;

  &:focus,
  &:hover {
    box-shadow: 0 0 ${remy(40)} rgba(0,0,0,.15);
  }

  &.flipped {
    & > div:first-of-type { // Front side of the card
      transform: perspective(1000px) rotateY(-180deg);
    }

    & > div:last-of-type { // Back side of the card
      transform: perspective(1000px) rotateY(0deg);
    }
  }
`

// Card sides
const CardSide = css`
  position: absolute;
  top: 0;
  left: 0;
  overflow: hidden;
  padding: ${remy(24)};
  display: flex;
  flex-direction: column;
  justify-content: center;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  transition: all .25s ease-in-out;
`

// Card side - front
const CardFront = sc.div`
  ${CardSide};

  font-weight: bold;
  text-align: center;
`

// Card side - back
const CardBack = sc.div`
  ${CardSide};

  transform: rotateY(-180deg);
`

// Card content
const CardNumber = sc.span`
  display: block;
  font-size: ${remy(24)};
`

const CardTitle = sc.h2`
  font-size: ${remy(21)};
`

const CardDescription = sc.span`
  font-size: ${remy(16)};
`

// Create layout component
class Layout extends React.Component {
  flipCard(event) {
    event.currentTarget.classList.toggle('flipped')
  }

  render() {
    return (
      <LayoutWrapper>
        <GridContainer>
          <GridRow>
            <GridColumn sm='6' lg='4'>
              <Card onClick={this.flipCard.bind(this)}>
                <CardFront>
                  <CardNumber>1.</CardNumber>

                  <CardTitle>Card</CardTitle>
                </CardFront>

                <CardBack>
                  <CardDescription>Rand's stated goal for writing the novel was "to show how desperately the world needs prime movers and how viciously it treats them" and to portray "what happens to the world without them".</CardDescription>
                </CardBack>
              </Card>
            </GridColumn>

            <GridColumn sm='6' lg='4'>
              <Card onClick={this.flipCard.bind(this)}>
                <CardFront>
                  <CardNumber>2.</CardNumber>

                  <CardTitle>Card</CardTitle>
                </CardFront>

                <CardBack>
                  <CardDescription>The core idea for the book came to her after a 1943 telephone conversation with a friend, who asserted that Rand owed it to her readers to write fiction about her philosophy.</CardDescription>
                </CardBack>
              </Card>
            </GridColumn>

            <GridColumn sm='6' lg='4'>
              <Card onClick={this.flipCard.bind(this)}>
                <CardFront>
                  <CardNumber>3.</CardNumber>

                  <CardTitle>Card</CardTitle>
                </CardFront>

                <CardBack>
                  <CardDescription>To produce Atlas Shrugged, Rand conducted research on the American railroad industry. Her previous work on a proposed (but never realized) screenplay.</CardDescription>
                </CardBack>
              </Card>
            </GridColumn>

            <GridColumn sm='6' lg='4'>
              <Card onClick={this.flipCard.bind(this)}>
                <CardFront>
                  <CardNumber>4.</CardNumber>

                  <CardTitle>Card</CardTitle>
                </CardFront>

                <CardBack>
                  <CardDescription>Atlas Shrugged is set in a dystopian United States at an unspecified time, in which the country has a "National Legislature" instead of Congress and a "Head of State" instead of a President.</CardDescription>
                </CardBack>
              </Card>
            </GridColumn>
          </GridRow>
        </GridContainer>
      </LayoutWrapper>
    )
  }
}

// Render Layout React element into the DOM
ReactDOM.render(
  <Layout />,
  container
)

Answer 1

從您顯示的代碼中只需更改以下內容

將class Layout...替換為const Layout = () => {然后

用以下代碼替換flipCard function

const flipCard = (event) =>  {
    event.currentTarget.classList.toggle('flipped')
}

刪除render() {行（不要忘記匹配的}

然后在您的 onClick 函數{this.flipCard...}替換為{flipCard}並且不需要更多更改