Changing Delimeter of Multiple Items Returned by a osascript/javascript File Select Dialog

I have a little zsh script I'm coding to run on MacOS. Been a bash/shell scripter for 25+ years, so it hasn't been all bad. Part of its function is to have the user select a file (or files) from a dialog using this little bit of osascript/javascript:

IMAGES="$(osascript -l JavaScript -e 'a=Application.currentApplication();a.includeStandardAdditions=true;a.chooseFile({withPrompt:"Select Image(s)",multipleSelectionsAllowed:"true"}).toString()')"

The selected files (three in this example) get dumped into the $IMAGES variable with a comma between each of them.

/Users/anderson/Pictures/1890-1899/1898/5-3-1898 John Gansemer & Lena Gansemer (nee Koltes).jpg,/Users/anderson/Pictures/1890-1899/1898/1898 Hans, Mary Anderson Wedding Photo 600dpi.jpg,/Users/anderson/Pictures/1890-1899/1898/1898 Hans. Mary Anderson Wedding Photo.jpg

Is there a way to get the delimiter to be something else (a pipe or something similar) that is less likely to show up in file or folder names that I am grabbing?

I've found references across the interwebs to the following the toString with a ".join" function, but I can't get the syntax right and/or might be barking up the wrong tree anyway.

Thanks,

Bill

Solution

In zsh, you can process strings with null bytes (unlike bash). Since NULs are not allowed in macOS filenames, it's an ideal delimiter. zsh also has a parameter expansion flag that will split a string on null bytes:

imagesStr="$(osascript -l JavaScript -e '
  a=Application.currentApplication();
  a.includeStandardAdditions=true;
  a.chooseFile({withPrompt:"Select Image(s)",multipleSelectionsAllowed:"true"})
    .join("\0")')"
local -a imagesAry=(${(0)imagesStr})

The code above incorporates @red_menace's suggestion in the comments to call .join("\0") instead of .toString().

The parameter expansion and command substitution can be nested:

local -a images=(${(0)"$(osascript -l JavaScript -e '
  a=Application.currentApplication();
  a.includeStandardAdditions=true;
  a.chooseFile({withPrompt:"Select Image(s)",multipleSelectionsAllowed:"true"})
    .join("\0")')"}
)
print -l $#images $images
#=> 3
#=> /Users/me/Documents/Screen Shot 2025-08-25 at 1.42.10 PM.png
#=> /Users/me/Documents/Screen Shot 2025-09-02 at 1.52.27 PM.png
#=> /Users/me/Documents/Screen Shot 2025-09-02 at 1.53.41 PM.png