How to know if an app is installed ?

Question

hi,

I want to launch an app #2 inside my app #1 or if it is not installed, redirect to the store.

In app #2, I register a specific file Extension (for example : .myspecificapp) described in the documentation : How to handle file activation 

In app #1, I use the Windows.System.Launcher :

// Path to the file to launch, relative to the package's install directory.
    var fileToLaunch = "files\\file.myspecificapp";

    // Launch a .png file that came with the package.
    function launchFile() {
        // First, get the image file from the package's image directory.
        
        Windows.ApplicationModel.Package.current.installedLocation.getFileAsync(fileToLaunch).then(
            function (file) {
                // Now launch the retrieved file.
                Windows.System.Launcher.launchFileAsync(file).then(
                    function (success) {
                        if (success) {
                            WinJS.log && WinJS.log("File " + file.name + " launched.", "sample", "status");
                        } else {
                            WinJS.log && WinJS.log("File launch failed.", "sample", "error");
                        }
                    });
            });
    }

But the problem is if app #2 is not installed on my system, Metro shows a popup as if I had enabled the displayApplicationPicker to true. In this case, I would like redirect the user to the store.

Is it possible to know if an application is installed or have you another idea to implement this case ?