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Adding Component Duplication To Lona

March 28, 2019

As you might know, I’ve decided to proceed with making more contributions to Lona, and earlier this week I had an opportunity to add a new feature to this app. In this post, I’ll give you an overview of my contribution.

Feature Request

Users often create new components based on the existing ones, and the only way to do it was to go to Finder and copy & paste a component file. So, there was a feature request to add component duplication support to the File Navigator.

First, let’s take a look at the context menu of the file in File Navigator:

My task was to add a new option called “Duplicate As…” to the context menu, and once the option was selected, it should display the Save dialog. After the user typed a file name, selected location for it and pressed “Save”, the program should open a newly created component in the Component Editor.

🔗 Issue description

Implementation

There is a function menuForFile, which creates a context menu, in the FileNavigator class, and that’s the place, where I needed to place my new code:

// Check if selected file has a ".component" extension
if NSURL(fileURLWithPath: path).pathExtension == "component" {
    menu.addItem(NSMenuItem(title: "Duplicate As...", onClick: {
        var saveURL: String
        // Show Save Dialog
        let dialog = NSSavePanel()
        dialog.title = "Save .component file"
        dialog.showsResizeIndicator = true
        dialog.showsHiddenFiles = false
        dialog.canCreateDirectories = true
        dialog.allowedFileTypes = ["component"]
        dialog.directoryURL = URL(fileURLWithPath: path).deletingLastPathComponent()
        // User canceled the save. Don't swap out the document.
        if dialog.runModal() != NSApplication.ModalResponse.OK {
            return
        }
        guard let url = dialog.url else { return }
        saveURL = url.path
// Try to copy file. If successful, open the file in the Component Editor. Otherwise, display an alert with an appropriate message.
        do {
             try FileManager.default.copyItem(atPath: path, toPath: saveURL)
        } catch {
             let alert = NSAlert()
             alert.messageText = "Couldn't copy component to \(saveURL)"
             alert.addButton(withTitle: "OK")
             alert.runModal()
             return
        }
        self.onAction?(saveURL)
    }))
}

Result

🔗 Pull request