[Feature improvement] Disable preview window from shellscript

[yutkat]

• I have read through the manual page (man fzf)
• I have the latest version of fzf
• I have searched through the existing issues

Info

• OS
  • Linux
  • Mac OS X
  • Windows
  • Etc.
• Shell
  • bash
  • zsh
  • fish

Problem / Steps to reproduce

I don't want to display the preview window when shellscript returns empty string.
I want to always display the preview window, But I want to control only the specific pattern from shellscript.

export FZF_DEFAULT_OPTS='--preview "~/.zsh/rc/myplugins/fzf-preview.sh {}"'

if [[ -e ${input} && $(file --mime ${input}) =~ /directory ]]; then
  ls -1 --color=always ${input}
elif [[ -e ${input} && $(file --mime ${input}) =~ binary ]]; then
  echo -ne "" # I don't want to show the preview window
elif [[ ${input} =~ .*:[[:digit:]]*:.* ]]; then
  # etc
fi

[jandamm]

I was about to write a similar feature request.

Two issues I can see here is having the preview open and close when having a list where only some items have a preview.
Also when using cat an empty file wouldn't show a preview. This could be confusing.

[vovcacik]

Hide preview window, when preview is empty string?