如何在React组件中使用switch语句?

我有一个React组件，在组件的渲染方法中，我有这样的东西:

render() {
    return (
        <div>
            <div>
                // removed for brevity
            </div>

           { switch(...) {} }

            <div>
                // removed for brevity
            </div>
        </div>
    );
}

Now the point is that I have two div elements, one at the top and one at the bottom, that are fixed. In the middle I want to have a switch statement, and according to a value in my state I want to render a different component. So basically, I want the two div elements to be fixed always, and just in the middle to render a different component each time. I'm using this to implement a multi-step payment procedure). Though, as is the code currently it doesn't work, as it gives me an error saying that switch is unexpected. Any ideas how to achieve what I want?

当前回答

一种在渲染块中使用条件操作符表示一种开关的方法:

{(someVar === 1 &&
    <SomeContent/>)
|| (someVar === 2 &&
    <SomeOtherContent />)
|| (this.props.someProp === "something" &&
    <YetSomeOtherContent />)
|| (this.props.someProp === "foo" && this.props.someOtherProp === "bar" &&
    <OtherContentAgain />)
||
    <SomeDefaultContent />
}

应该确保条件严格返回布尔值。

2018-08-07 21:09:29

其他回答

React组件中的Switch-Case语句可以如下使用:

<div  id="time-list">
{   
    (() => {
        switch (groupByFilterId) {
            case 0:/*Case 0 */
                return (
                    <div>Case 0</div>
                )
               break;
           case 1: /*Case 1 */
           return ( 
            <div>Case 1</div>
            )
            break;
           case 2:/*Case 2 */
           return ( 
            <div>Case 2</div>
            )
            break;
        }
     })()}

      
       
    
    </div>

2021-05-09 12:05:43

让它变得简单，只需使用许多if语句。

例如:

<Grid>
   {yourVar==="val1"&&(<> your code for val1 </>)}
   {yourVar==="val2"&&(<> your code for val2 </>)}
   .... other statments
</Grid>

2021-04-28 14:28:50

我正在使用这个帮助器，它允许我在JSX中有开关语句

// in helpers folder const switchTrue = (object) => { const { default: defaultValue, ...rest } = object; const obj = { default: defaultValue, ...rest }; const result = Object.keys(obj).reduce((acc, cur) => { return { ...acc, [cur === 'default' ? 'true' : cur]: obj[cur], }; }, {}); return result['true']; }; const Sample = () => { const isDataLoading = false; return ( <div> { switchTrue({ [`${isDataLoading}`]: <div>Loading</div>, [`${!isDataLoading}`]: <div>Data Ready</div>, default: <div>Default</div>, }) } </div> ) } ReactDOM.render( <Sample/>, document.getElementById("react") ); <script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script> <div id="react"></div>

2021-12-23 09:49:52

这是因为switch语句是一个语句，但这里javascript需要一个表达式。

虽然，不建议在呈现方法中使用switch语句，但你可以使用自调用函数来实现这一点:

render() {
    // Don't forget to return a value in a switch statement
    return (
        <div>
            {(() => {
                switch(...) {}
            })()}
        </div>
    );
}

2017-10-05 19:02:10

我知道我有点晚了，但我认为这个实现可能会有所帮助

您可以使用条件操作符来呈现组件

如果你有下面的switch语句

switch(value) {
    case CASE1:
        return <Case1Component/>

    case CASE2:
        return <Case2Component/>

    case CASE3:
        return <Case3Component/>

    default:
        return <DefaultComponent/>
}

你可以像这样把它转换成react组件

const cases = [CASE0, CASE1, CASE2]
// Reminds me of 'react-router-dom'
return (
    <div>
        {value === cases[0] && <Case0Component/>}
        {value === cases[1] && <Case1Component/>}
        {value === cases[2] && <Case2Component/>}
        {!cases.includes(value) && <DefaultComponent/>}
    </div>
)

2021-06-21 13:46:00

如何在React组件中使用switch语句?

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