node app.js 出现bug

[wappoint]

module.js:440 throw err; ^

Error: Cannot find module 'debug' at Function.Module._resolveFilename (module.js:438:15) at Function.Module._load (module.js:386:25) at Module.require (module.js:466:17) at require (internal/module.js:20:19) at Module._compile (module.js:541:32) at Object.Module._extensions..js (module.js:550:10) at Module.load (module.js:456:32) at tryModuleLoad (module.js:415:12) at Function.Module._load (module.js:407:3)