因为我是bug体质，所以才来写博客。
Vue安装依赖包警告：
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@^1.1.2 (node_modules\ch
okidar\node_modules\fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@
1.2.4: wanted {"os":"darwin","arch":"any"} (current: {"os":"win32","arch":"x64"})
npm WARN ajv-keywords@3.2.0 requires a peer of ajv@^6.0.0 but none was installed.
这个是因为fsevents是mac os 系统下的依赖包，所以提出警告。
