lib/util.js
function injectWatcher(handler) {
        return function(module, filename) {
            fs.watchFile(filename, watcher);
            handler(module, filename);
        };
    }
function injectWatcher(handler) {
        return function(module, filename) {
            fs.watchFile(filename, watcher);
            handler(module, filename);
        };
    }
function injectWatcher ( handler ) { return function ( module , filename ) { fs . watchFile ( filename , watcher ) ; handler ( module , filename ) ; } ; }
hijack each module extension handler, and watch the file
hijack each module extension handler and watch the file