JavaScript has a compact syntax for writing a conditional expression — the conditional operator or “ternary operator.” Instead of this: if (isPacked) { return {name} ✔; } return {name}; You can write this: return ( {isPacked ? name + ' ✔' : name} ); You can read it...
To learn more, see the ternary operator section.Exercise? Which one of these two code blocks is a correct way of adding a conditional statement in React? function Glass() { return ( <> {5 > 2 && Hello } </> );} function Glass() { return ( <> {5 > 2 &&} Hello </> );}Su...
// Conditional rendering with ternary operator let isDrinkCoffee = role === "programmer" ? true : false; 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 这是函数返回值的条件渲染示例: // Conditional rendering with common if else function isDrinkCoffee(role) { if (role === "programmer") { r...
这是使用 三元运算符(conditional ternary operator)编写的相同组件。 const MyComponent = ({ name }) => ( {name ? `Hello ${name}` : 'Please sign in'} ); 请注意这段代码与上面的例子相比是多么简洁。 有几点需要注意。因为我们使用了箭头函数的单语句形式,所以隐含了return 语句。另外,使用三元...
React 中的条件渲染有以下几种方式: if 语句 三元操作符(ternary operator) 逻辑 && 操作符 switch.. case.. 语句 枚举(enums) 多层条件渲染(multi-level conditional reandering) 使用高阶组件 1.if 语句 在React中使用if语句条件渲染是最简单的。比如List组件如果没有任何items,可...React—条件渲染不同的组...
To put any expression we need to use {} , so instead of if use && operator or ternary operator for conditional rendering. 通过使用 三元运算符: var chartGraphContent = { this.state.modalityGraph['nca'] > 0 ? <Chart chartType="ColumnChart" data = { this.state.modalityGraph?this....
Another way to implement conditional rendering is the ternary operator:condition ? true : false; The ternary operator is suitable for code without much logic: it just returns different results directly according to different conditions class App extends React.Component { ...
在本章中,我们将通过创建一个显示应用主页的基于函数的组件,开始使用 TypeScript 构建 Q&A React 前端。这将在列表中显示最近提出的问题。作为本文的一部分,我们将花时间了解 strict 模式和 JSX。然后,我们将继续使用道具创建更多组件,以便在它们之间传递数据。在本章末尾,我们将开始了解组件状态,以及它如何使组件与...
Another way is using the logical AND operator as shown below:function showLoggenInUser(props) { return props.isAuthenticated && Welcome back, {props.username}!; }If you’re interested in learning more, we explore nine methods of React conditional rendering in this article, with examples to...
Conditional rendering refers to changing the behavior of an app depending on its state. For instance, you can change the greeting message of your React app to dark during the night. This way you have a different display message depending on the time of day. ...