Cannot find module 'ws'

[vvangxp]

运行 Server.js 时出现的提示，该怎么解决？

[vvangxp]

Debugger listening on [::]:15454
module.js:471
throw err;
^

Error: Cannot find module 'ws'
at Function.Module._resolveFilename (module.js:469:15)
at Function.Module._load (module.js:417:25)
at Module.require (module.js:497:17)
at require (internal/module.js:20:19)
at Object. (/home/ec2-user/environment/shadowws/server.js:13:15)
at Object. (/home/ec2-user/environment/shadowws/server.js:230:4)
at Module._compile (module.js:570:32)
at Object.Module._extensions..js (module.js:579:10)
at Module.load (module.js:487:32)
at tryModuleLoad (module.js:446:12)