react-router-dom switch & match

Renders the first child <Route> or <Redirect> that matches the location.

If the URL is /about, then <About>, <User>, and <NoMatch> will all render because they all match the path. This is by design, allowing us to compose <Route>s into our apps in many ways, like sidebars and breadcrumbs, bootstrap tabs, etc.

import { Route } from "react-router";

let routes = (
  <div>
    <Route path="/about">
      <About />
    </Route>
    <Route path="/:user">
      <User />
    </Route>
    <Route>
      <NoMatch />
    </Route>
  </div>
);

Occasionally, however, we want to pick only one <Route> to render. If we’re at /about we don’t want to also match /:user (or show our “404” page). Here’s how to do it with Switch:

import { Route, Switch } from "react-router";

let routes = (
  <Switch>
    <Route exact path="/">
      <Home />
    </Route>
    <Route path="/about">
      <About />
    </Route>
    <Route path="/:user">
      <User />
    </Route>
    <Route>
      <NoMatch />
    </Route>
  </Switch>
);

Now, if we’re at /about, <Switch> will start looking for a matching <Route>. <Route path="/about"/> will match and <Switch> will stop looking for matches and render <About>. Similarly, if we’re at /michael then <User> will render.

We can manually set the variable parameters like this: 

 <Route path="/scan/detail/:trx/:tokenAddress" component={ScanDetail} />

And then we can get this parameter in the subcomponent:

let { tokenAddress } = this.props.match.params;

A match object contains information about how a <Route path> matched the URL. match objects contain the following properties:

• params - (object) Key/value pairs parsed from the URL corresponding to the dynamic segments of the path
• isExact - (boolean) true if the entire URL was matched (no trailing characters)
• path - (string) The path pattern used to match. Useful for building nested <Route>s
• url - (string) The matched portion of the URL. Useful for building nested <Link>s

You’ll have access to match objects in various places:

• Route component as this.props.match
• Route render as ({ match }) => ()
• Route children as ({ match }) => ()
• withRouter as this.props.match
• matchPath as the return value
• useRouteMatch as the return value

If a Route does not have a path, and therefore always matches, you’ll get the closest parent match. Same goes for withRouter.

react-router-dom switch & match

原文：https://www.cnblogs.com/xulei1992/p/15179717.html