npm Error: Cannot find module 'are-we-there-yet'

npm 损坏了，are-we-there-yet是npm所依赖的npmlog依赖的一个包，重新安装npm即可：

➜  lib npm
module.js:550
    throw err;
    ^

Error: Cannot find module 'are-we-there-yet'
    at Function.Module._resolveFilename (module.js:548:15)
    at Function.Module._load (module.js:475:25)
    at Module.require (module.js:597:17)
    at require (internal/module.js:11:18)
    at Object.<anonymous> (/usr/local/lib/node_modules/npm/node_modules/npmlog/log.js:2:16)
    at Module._compile (module.js:653:30)
    at Object.Module._extensions..js (module.js:664:10)
    at Module.load (module.js:566:32)
    at tryModuleLoad (module.js:506:12)
    at Function.Module._load (module.js:498:3)

解决办法：

cd /usr/local/lib/node_modules
mv npm /tmp
sudo curl -L registry.npmjs.com/npm/-/npm-6.13.7.tgz |sudo tar xz --transform="s:^package:npm:"
➜  ~ npm -v
6.13.7

npm-6.13.7.tgz 是我使用的版本，你也可以在官网查询相应的版本号。
https://www.npmjs.com/package/npm

 参考：

https://stackoverflow.com/questions/31025048/npm-doesnt-work-get-always-this-error-error-cannot-find-module-are-we-the