npm run dev 出错的解决办法

bogon:~ yan$ cd my-project

bogon:my-project yan$ npm run dev

> my-project@1.0.0 dev /Users/yan/my-project

> node build/dev-server.js

module.js:471

    throw err;

    ^

Error: Cannot find module 'shelljs'

    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.<anonymous> (/Users/yan/my-project/build/check-versions.js:4:13)

    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)

    at Function.Module._load (module.js:438:3)

ERR! code ELIFECYCLE

errno 1

ERR! my-project@1.0.0 dev: `node build/dev-server.js`

ERR! Exit status 1

ERR! Failed at the my-project@1.0.0 dev script.

ERR! This is probably not a problem with npm. There is likely additional logging output above.

ERR! A complete log of this run can be found in:

ERR!     /Users/yan/.npm/_logs/2017-09-13T09_56_03_996Z-debug.log

bogon:my-project yan$ npm install shelljs

notice created a lockfile as package-lock.json. You should commit this file.

+ shelljs@0.7.8

added 16 packages in 32.151s

解决办法：error提示缺少什么模块就 npm install XXX ，缺少什么模块就运行安装命令；

bogon:my-project yan$ npm run dev

> my-project@1.0.0 dev /Users/yan/my-project

> node build/dev-server.js

 > Starting dev server...

直到启动dev成功；