Strings passed in as an argument to --eval (or -e), or piped to node via STDIN, are treated as [ES modules][] when the --input-type=module flag is set.

    1. node --input-type=module --eval "import { sep } from 'path'; console.log(sep);"
    3. echo "import { sep } from 'path'; console.log(sep);" | node --input-type=module

    For completeness there is also --input-type=commonjs, for explicitly running string input as CommonJS. This is the default behavior if --input-type is unspecified.