extname(path) {
		const filename = path.split("/").slice(-1)[0];
		if (/.+\..*$/.test(filename)) {
			return /(?:\.([^.]*))?$/.exec(filename)[0] || "";
		}

		return "";
	}
returns the extension of the path, from the last occurrence of the . (period)
character to end of string in the last portion of the path.
If there is no . in the last portion of the path, or if there are no . characters
other than the first character of the basename of path (see path.basename()) , an
empty string is returned.
@param {string} path