src/utils.js
function isFresh(req, res) {
	if ((res.statusCode >= 200 && res.statusCode < 300) || 304 === res.statusCode) {
		return fresh(req.headers, {
			"etag": res.getHeader("ETag"),
			"last-modified": res.getHeader("Last-Modified")
		});
	}
	return false;
}
function isFresh(req, res) {
	if ((res.statusCode >= 200 && res.statusCode < 300) || 304 === res.statusCode) {
		return fresh(req.headers, {
			"etag": res.getHeader("ETag"),
			"last-modified": res.getHeader("Last-Modified")
		});
	}
	return false;
}
function isFresh ( req , res ) { if ( ( res . statusCode >= 200 && res . statusCode < 300 ) || 304 === res . statusCode ) { return fresh ( req . headers , { "etag" : res . getHeader ( "ETag" ) , "last-modified" : res . getHeader ( "Last-Modified" ) } ) ; } return false ; }
Check the data freshness.

@param {*} req
@param {*} res

@returns {Boolean}
Check the data freshness .