`type` but leveled up - cat the contents of aliases which point to scripts

.wat.sh

#!/bin/bash
#
# Usage: 'source /path/to/wat.sh <cmd>'
#
# Outputs 'type <cmd>' or, if it's an alias, cats the script it's aliased to.
# Needs to be sourced, not run, because it needs access to all current shell
# aliases/variables.

WAT_ALIAS_PAT=
WAT_ALIAS_PAT+="("
WAT_ALIAS_PAT+="(?<=is aliased to \`)"
WAT_ALIAS_PAT+="|"
WAT_ALIAS_PAT+="(?<=is aliased to \`source )"
WAT_ALIAS_PAT+=")"
WAT_ALIAS_PAT+="[~/].*"
WAT_ALIAS_PAT+="(?=')"

WAT_TYPE_OUT="$(type "$@")"
WAT_TYPE_GREP="$(grep -oP "${WAT_ALIAS_PAT}" <<<"${WAT_TYPE_OUT}")"

echo "${WAT_TYPE_OUT}"

if [[ "${WAT_TYPE_GREP}" ]]; then
  cat "${WAT_TYPE_GREP/#\~/$HOME}"
fi

# Since this script is designed to be sourced, not invoked in a subshell, clean
# up after ourselves.
WAT_ALIAS_PATH=
WAT_TYPE_GREP=
WAT_TYPE_OUT=