20211013 - about exact in react-router

<Route exact path="/" component={Home} />  // explanation: / -> Home; /blahblah -> blank
<Route exact path="/:id" component={Pod} />  // explanation: /:id -> Pod; /:id/blahblah -> blank
<Route path="/" component={Home} /> // explanation: / -> Home; /blahblah -> Home

exact的意思是精确匹配路径

加上exact之后，表明只匹配到path里的内容为止，如果不加exact，往path后面加上内容也会匹配到相同的组件。