后台安装报错

[weizhixiangcoder]

[root@localhost niuniu_server]# npm install
npm WARN [email protected] No repository field.

removed 3 packages in 1.127s
found 0 vulnerabilities

[root@localhost niuniu_server]# node launch.js
module.js:544
throw err;
^

Error: Cannot find module 'express'
at Function.Module._resolveFilename (module.js:542:15)
at Function.Module._load (module.js:472:25)
at Module.require (module.js:585:17)
at require (internal/module.js:11:18)
at Object. (/root/niuniu_server/center_server/centerServer.js:3:17)
at Module._compile (module.js:641:30)
at Object.Module._extensions..js (module.js:652:10)
at Module.load (module.js:560:32)
at tryModuleLoad (module.js:503:12)
at Function.Module._load (module.js:495:3)