基本上,我有一个react组件,它的render()函数体如下所示:(这是我的理想之一,这意味着它目前不工作)

render(){
    return (
        <div>
            <Element1/>
            <Element2/>

            // note: logic only, code does not work here
            if (this.props.hasImage) <ElementWithImage/>
            else <ElementWithoutImage/>

        </div>
    )
}

当前回答

if then的简写

 { condition ? <Element1/> : null }

其他回答

仅当:

{condition1 && 
(<div> condition1 true </div>)}

对于if和else:

{condition1 ? 
(<div> condition1 true </div>)
:(<div> condition1 false </div>)}

if, else if, else:

{condition1 ? 
(<div>condition1 true</div>)
:(condition2) && 
(<div>condition2 true</div>)
:(<div>both conditions false</div>)}

下面的代码,你可以使用的If条件反应在侧返回

                                    {(() => {if (true) {return ( <div><Form>
                                        <Form.Group as={Row} style={{ marginLeft: '15px', marginRight: '15px', marginBlock: '0px' }} >
                                            <Form.Label className="summary-smmdfont" style={{ flex: '1 0 auto', marginBlock: '0px' }}>   uyt</Form.Label>
                                            <Form.Label className="summary-smmdfont"style={{ textAlignLast: 'Right', flex: '1 0 auto', marginBlock: '0px' }}>
                                                09</Form.Label>
                                        </Form.Group>
                                        </Form>

                                    </div>);
                    }})()}

如果你想使用If, else If和else则使用此方法

           {this.state.value === 0 ? (
                <Component1 />
            ) : this.state.value === 1 ? (
              <Component2 />
            ) : (
              <Component3 />
            )}

你也可以写If语句组件。这是我在我的项目中使用的。

组件/ IfStatement.tsx

import React from 'react'

const defaultProps = {
    condition: undefined,
}

interface IfProps {
    children: React.ReactNode
    condition: any
}

interface StaticComponents {
    Then: React.FC<{ children: any }>
    Else: React.FC<{ children: any }>
}

export function If({ children, condition }: IfProps): any & StaticComponents {
    if (React.Children.count(children) === 1) {
        return condition ? children : null
    }

    return React.Children.map(children as any, (element: React.ReactElement) => {
        const { type: Component }: any = element

        if (condition) {
            if (Component.type === 'then') {
                return element
            }
        } else if (Component.type === 'else') {
            return element
        }

        return null
    })
}

If.defaultProps = defaultProps

export function Then({ children }: { children: any }) {
    return children
}

Then.type = 'then'

export function Else({ children }: { children: any }) {
    return children
}

Else.type = 'else'

If.Then = Then as React.FC<{ children: any }>
If.Else = Else as React.FC<{ children: any }>

export default If

使用的例子:

<If condition={true}>
   <If.Then>
        <div>TRUE</div>
   </If.Then>
   <If.Else>
        <div>NOT TRUE</div>
   </If.Else>
</If>

如果你有2个不同的依赖关系,你也可以在条件操作符中使用条件(三元)操作符。

{
(launch_success)
  ?
  <span className="bg-green-100">
    Success
  </span>
  :
  (upcoming)
    ?
    <span className="bg-teal-100">
      Upcoming
    </span>
    :
    <span className="bg-red-100">
      Failed
    </span>
}