npm install 速度慢

换为国内镜像：
npm install --registry=http://registry.npm.taobao.org

永久设置：
npm config set registry http://registry.npm.taobao.org

mac安装node之后运行npm出错

module.js:341
    throw err;
    ^

Error: Cannot find module 'npmlog'
    at Function.Module._resolveFilename (module.js:339:15)
    at Function.Module._load (module.js:290:25)
    at Module.require (module.js:367:17)
    at require (internal/module.js:16:19)
    at /usr/local/lib/node_modules/npm/bin/npm-cli.js:20:13
    at Object.<anonymous> (/usr/local/lib/node_modules/npm/bin/npm-cli.js:76:3)
    at Module._compile (module.js:413:34)
    at Object.Module._extensions..js (module.js:422:10)
    at Module.load (module.js:357:32)
    at Function.Module._load (module.js:314:12)

因为之前卸载node没有卸载干净，解决方法：brew uninstall --force node
rm -rf /usr/local/lib/node_modules
rm /usr/local/bin/npm
brew install node

https://stackoverflow.com/a/39504056/5685754