Allow the async-loader preload method to conditionally execute the first argument callback function only if it's a function (#1276)
Allow the async-loader preload method to conditionally execute the first argument callback function only if it's a function (#1276)

Co-authored-by: Jason Miller <7262152a08bba599e92847732983e56b3b3331e2@users.noreply.github.com>
developit/preact-cli,developit/preact-cli