# Ensure JavaScript development dependencies are installed.
yarn check -s 2>/dev/null
if["$?"-ne"0"];then
printf"Drupal's JavaScript development dependencies are not installed. Run 'yarn install' inside the core directory.\n"
printf"Drupal's JavaScript development dependencies are not installed or cannot be resolved. Run 'yarn install' inside the core directory, or 'yarn check -s' to list other errors.\n"