flake + fzf = ❤

flake-fzf.sh

#!/usr/bin/env bash
set -euo pipefail
system=$(nix-instantiate --eval --expr 'builtins.currentSystem' --json | jq -r)
selection=$(
nix flake show --json | 
  jq -r '
  [
    leaf_paths as $path | 
    {"key": $path | join("."), "value": getpath($path)} | 
    select( .key | endswith("type")) |
    select(.value != "unknown") 
  ] |
  map({ "key": "\(.key | sub(".type"; ""))", "value": .value}) |
  from_entries |
  to_entries[] |
  [.key, .value] |
  @tsv' | 
  fzf --layout=reverse --border \
    --preview "nix show-derivation .#{1} 2>/dev/null" \
    --delimiter "\t" --padding=1 \
    --bind 'btab:change-query(configuration )' \
    --bind "tab:change-query($system )")

selectedPath="$(echo -n "$selection" | cut -d$'\t' -f1 | tr -d '\n')"
selectedType="$(echo -n "$selection" | cut -d$'\t' -f2 | tr -d '\n')"
case $selectedType in
	"nixos-configuration")
		set -x
		nix build ".#$selectedPath.config.system.build.toplevel"
		;;
	*)
		set -x
		nix build ".#$selectedPath"
		;;
esac