Extending View Bridges

When extending a View class it is often (not always) necessary to extend the View Bridge as well to provide client side support for the new features being added.

rhubarb.vb.create('MyExtendedViewBridge', function(parent){
    return {

    };
}, rhubarb.viewBridgeClasses.MyBaseViewBridge);

The key difference from creating a new View Bridge is that we pass a third argument to create which is a reference to the base View Bridge class previously registered (registered View Bridges are added to the rhubarb.viewBridgeClasses object). That class is passed to our creation function as a handy variable parent. This allows us to call the parent implementation of functions when we 'override' them:

rhubarb.vb.create('MyExtendedViewBridge', function(parent){
    return {
        onReady(){
            // Some extended type behaviour would go here

            // Now call the base implementation:
            parent.onReady.call(this); 
        }  
    };
}, rhubarb.viewBridgeClasses.MyBaseViewBridge);

Calling the parent is often extremely important but all too easily forgotten.

Installing the extended View Bridge

In your View class you need to use the name of your extended view and carefully construct a deployment package to contain both View Bridge files in the correct order:

class MyExtendedView extends MyBaseView
{
    public function getDeploymentPackage()
    {
        return new LeafDeploymentPackage(
            __DIR__ . '/MyBaseViewBridge.js',
            __DIR__ . '/MyExtendedViewBridge.js',
            );
    }

    protected function getViewBridgeName()
    {
        return 'HomepageViewBridge';
    }
}

To ensure the View Bridges are loaded in the correct order it's more usual to call the parent View's getDeploymentPackage() method and add your extended View Bridge file to the list:

class MyExtendedView extends MyBaseView
{
    public function getDeploymentPackage()
    {
        $package = parent::getDeploymentPackage();
        $package->resourcesToDeploy[] = __DIR__ . '/MyExtendedViewBridge.js';

        return $package;
    }
}