Copy string keys from a locale JSON file to another

lang-cp

#!/bin/bash
###########################################################################
# USAGE Example:
#     lang-cp from_dir from_file_prefix to_dir key1 key2 key3@KEY_3_NEW_NAME key4
###########################################################################
from_list=$(find $1 | grep "$2_.*json")
echo "Copying from $2..."
for f in $from_list; do
  lang=$(echo $f | cut -d '_' -f 2 | cut -d '.' -f 1)
  to_lang=${lang//-/_}
  to_file="$3/$to_lang/translation.json"
  for key in ${@:4}; do 
    as=$(node -e "if ('$key'.includes('@')) {console.log('$key'.split('@')[1])} else {console.log('$key')}")
    key=$(node -e "if ('$key'.includes('@')) {console.log('$key'.split('@')[0])} else {console.log('$key')}")
    echo -e "$2_$lang.json --> $to_lang/translation.json"
    echo -e "  from: $key"
    echo -e "  to:   $as"
    value=$(node -e "
      let from = $(cat $f);
      console.log(from[\"$key\"])
    ");
    node -e "
      let to = $(cat $to_file 2>/dev/null || echo '{}');
      if (\"$value\" !== 'undefined') {
        if (!to[\"$as\"]) to[\"$as\"] = \"$value\";
      }
      console.log(JSON.stringify(to, null, 2));
    " > $to_file;
  done
done

Special thanks to @jlubean for making improvements to lang-mv and thus creating this package!