To illustrate the use case for IndexRoute
, imagine the following route
config without it:
<Router>
<Route path="/" component={App}>
<Route path="accounts" component={Accounts}/>
<Route path="statements" component={Statements}/>
</Route>
</Router>
When the user visits /
, the App component is rendered, but none of the
children are, so this.props.children
inside of App
will be undefined.
To render some default UI you could easily do {this.props.children || <Home/>}
.
But now Home
can't participate in routing, like the onEnter
hooks,
etc. You render in the same position as Accounts
and Statements
, so
the router allows you have Home
be a first class route component with
IndexRoute
.
<Router>
<Route path="/" component={App}>
<IndexRoute component={Home}/>
<Route path="accounts" component={Accounts}/>
<Route path="statements" component={Statements}/>
</Route>
</Router>
Now App
can render {this.props.children}
and we have a first-class
route for Home
that can participate in routing.
If you were to <Link to="/">Home</Link>
in this app, it would always
be active since every URL starts with /
. This is a problem because
we'd like to link to Home
but only be active if Home
is rendered.
To have a link to /
that is only active when the Home
route is
rendered, use <IndexLink to="/">Home</IndexLink>
.