lib/errors.js
function notFound( req, res, next ) {
        var err = new Error( 'Not Found' );
        err.status = 404;

        next( err );
    }
function notFound( req, res, next ) {
        var err = new Error( 'Not Found' );
        err.status = 404;

        next( err );
    }
function notFound ( req , res , next ) { var err = new Error ( 'Not Found' ) ; err . status = 404 ; next ( err ) ; }
catch 404 and forward to error handler
catch 404 and forward to error handler