om/node_modules/os-tmpdir/index.js

'use strict';
var isWindows = process.platform === 'win32';
var trailingSlashRe = isWindows ? /[^:]\\$/ : /.\/$/;

// https://github.com/nodejs/node/blob/3e7a14381497a3b73dda68d05b5130563cdab420/lib/os.js#L25-L43
module.exports = function () {
	var path;

	if (isWindows) {
		path = process.env.TEMP ||
			process.env.TMP ||
			(process.env.SystemRoot || process.env.windir) + '\\temp';
	} else {
		path = process.env.TMPDIR ||
			process.env.TMP ||
			process.env.TEMP ||
			'/tmp';
	}

	if (trailingSlashRe.test(path)) {
		path = path.slice(0, -1);
	}

	return path;
};