Start with selection and target
The catalog and the user’s selection are different concepts. The catalog carries platform package identifiers; the selection determines which entries become output. Changing the target changes the supported packages and generated commands. Keeping those concerns separate makes the path from an interface selection to script text easier to inspect.
Where the file is created
downloadScript() converts generateScript() output to a Blob. The browser creates a temporary object URL, and the download filename uses the chosen platform’s extension. The user receives an inspectable file without a separate server endpoint preparing the download.
The resource lifecycle
Creating a temporary URL is only half the workflow. After starting the download, the link is removed from the DOM and URL.revokeObjectURL() releases the address. Creation and cleanup can be read in one function. This lifecycle keeps temporary-address management explicit when downloads are repeated.
Keep the boundary explicit
The downloaded script depends on the target machine’s package manager and catalog mappings. The source applies --cask to all Homebrew entries, so individual mappings still need checking. Generating a file and completing an installation are separate stages. The concrete output demonstrated here is a user selection becoming a setup script the user can review.