Kris Zhang

After run npm install, I get the following errors: ``` npm ERR! Linux 4.13.0-36-generic npm ERR! argv "/usr/local/n/versions/node/9.6.1/bin/node" "/usr/bin/npm" "install" npm ERR! node v9.6.1 npm ERR! npm v3.5.2 npm ERR!...

I got the reason, because the npm is old version. Use the following command to upgrade npm: ``` npm install -g npm ``` The strange is when you run npm...

how to solve this problem?

写的非常好！