wangjianqingdeMacBook-Air:~ wangjianqing$ java -version
java version "1.8.0_73"
Java(TM) SE Runtime Environment (build 1.8.0_73-b02)
Java HotSpot(TM) 64-Bit Server VM (build 25.73-b02, mixed mode)
wangjianqingdeMacBook-Air:~ wangjianqing$ node -v
v8.9.3
wangjianqingdeMacBook-Air:~ wangjianqing$ npm -v
5.5.1
wangjianqingdeMacBook-Air:~ wangjianqing$ python
Python 3.6.6 (v3.6.6:4cf1f54eb7, Jun 26 2018, 19:50:54)
[GCC 4.2.1 Compatible Apple LLVM 6.0 (clang-600.0.57)] on darwin
Type "help", "copyright", "credits" or "license" for more information.

wangjianqingdeMacBook-Air:~ wangjianqing$ npm install -g appium
/usr/local/Cellar/nvm/0.33.11/versions/node/v8.9.3/bin/appium -> /usr/local/Cellar/nvm/0.33.11/versions/node/v8.9.3/lib/node_modules/appium/build/lib/main.js

> appium-chromedriver@4.0.0 install /usr/local/Cellar/nvm/0.33.11/versions/node/v8.9.3/lib/node_modules/appium/node_modules/appium-chromedriver
> node install-npm.js

info Chromedriver Install Installing Chromedriver version '2.38' for platform 'mac' and architecture '64'
info Chromedriver Install Opening temp file to write chromedriver_mac64 to...
info Chromedriver Install Downloading https://chromedriver.storage.googleapis.com/2.38/chromedriver_mac64.zip...
RequestError: Error: connect ETIMEDOUT 216.58.217.251:443
    at new RequestError (/usr/local/Cellar/nvm/0.33.11/versions/node/v8.9.3/lib/node_modules/appium/node_modules/request-promise-core/lib/errors.js:14:15)
    at Request.plumbing.callback (/usr/local/Cellar/nvm/0.33.11/versions/node/v8.9.3/lib/node_modules/appium/node_modules/request-promise-core/lib/plumbing.js:87:29)
    at Request.RP$callback [as _callback] (/usr/local/Cellar/nvm/0.33.11/versions/node/v8.9.3/lib/node_modules/appium/node_modules/request-promise-core/lib/plumbing.js:46:31)
    at self.callback (/usr/local/Cellar/nvm/0.33.11/versions/node/v8.9.3/lib/node_modules/appium/node_modules/request/request.js:185:22)
    at emitOne (events.js:116:13)
    at Request.emit (events.js:211:7)
    at Request.onRequestError (/usr/local/Cellar/nvm/0.33.11/versions/node/v8.9.3/lib/node_modules/appium/node_modules/request/request.js:877:8)
    at emitOne (events.js:116:13)
    at ClientRequest.emit (events.js:211:7)
    at TLSSocket.socketErrorListener (_http_client.js:387:9)
    at emitOne (events.js:116:13)
    at TLSSocket.emit (events.js:211:7)
    at emitErrorNT (internal/streams/destroy.js:64:8)
    at _combinedTickCallback (internal/process/next_tick.js:138:11)
    at process._tickCallback (internal/process/next_tick.js:180:9)
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! appium-chromedriver@4.0.0 install: `node install-npm.js`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the appium-chromedriver@4.0.0 install script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.