--- id: if-else-in-JSX title: If-Else in JSX layout: tips permalink: if-else-in-JSX.html prev: inline-styles.html next: self-closing-tag.html --- `if-else` statements don't work inside JSX. This is because JSX is just syntactic sugar for function calls and object construction. Take this basic example: ```js // This JSX: React.render(<div id="msg">Hello World!</div>, mountNode); // Is transformed to this JS: React.render(React.createElement("div", {id:"msg"}, "Hello World!"), mountNode); ``` This means that `if` statements don't fit in. Take this example: ```js // This JSX: <div id={if (condition) { 'msg' }}>Hello World!</div> // Is transformed to this JS: React.createElement("div", {id: if (condition) { 'msg' }}, "Hello World!"); ``` That's not valid JS. You probably want to make use of a ternary expression: ```js React.render(<div id={condition ? 'msg' : ''}>Hello World!</div>, mountNode); ``` If a ternary expression isn't robust enough, you can use `if` statements to determine which components should be used. ```js var loginButton; if (loggedIn) { loginButton = <LogoutButton />; } else { loginButton = <LoginButton />; } return ( <nav> <Home /> {loginButton} </nav> ) ``` Try using it today with the [JSX compiler](/react/jsx-compiler.html).