> ## Documentation Index
> Fetch the complete documentation index at: https://doc.lucidworks.com/llms.txt
> Use this file to discover all available pages before exploring further.
# show:when
export const LwTemplate = ({title = "Key questions to get you started", icon = "sparkles", cta = "Powered by Agent Studio", linkHref = "https://lucidworks.com/demo/?utm_source=docs&utm_medium=referral&utm_campaign=docs_cta_ai"}) => {
const [isLoaded, setIsLoaded] = useState(false);
useEffect(() => {
const timer = setTimeout(() => {
setIsLoaded(true);
}, 500);
return () => clearTimeout(timer);
}, []);
return
{isLoaded && `
}} />}
Powered by Lucidworks Agent Studio
;
};
[localhost link]: http://localhost:3000/docs/4/app-studio/reference/tags/lightning.directive.showWhen
[mintlify link]: https://doc.lucidworks.com/docs/4/app-studio/reference/tags/lightning.directive.showWhen
[old doc.lw link]: https://doc.lucidworks.com/app-studio/4.2/1151
## Description
Show or hide element based on expression passed to it.
## Usage
as attribute
```xml wrap theme={"dark"}
...
```
#### Parameters
| Param | Type | Details |
| --------- | -------------- | ----------------------- |
| show-when | **expression** | Expression to evaluate. |
## Example
#### Source
```xml wrap theme={"dark"}
{{foo ? 'Hide' : 'Show'}}!
Hello World
```
```xml wrap theme={"dark"}
angular.module('lightning')
.controller('ExampleController', ['$scope','$timeout', function($scope,$timeout) {
$scope.foo = false;
$scope.alert = function(){
$scope.foo = !$scope.foo
};
}]);
```
#### Result
