安装node.js

https://nodejs.org/en/

This package will install:
• Node.js v8.11.1 to /usr/local/bin/node
• npm v5.6.0 to /usr/local/bin/npm

This package has installed:

• Node.js v8.11.1 to /usr/local/bin/node
• npm v5.6.0 to /usr/local/bin/npm

Make sure that /usr/local/bin is in your $PATH.