React Router with optional path parameter

I want to declare a path with an optional path parameter, hence when I add it the page to do something extra (e.g. fill some data):

> http://localhost/app/path/to/page <= render the page > http://localhost/app/path/to/page/pathParam <= render the page with > some data according to the pathParam

In my react router I have the following paths, in order to support the two options (this is a simplified example):

<Router history={history}>    
   <Route path="/path" component={IndexPage}>
      <Route path="to/page" component={MyPage}/>
      <Route path="to/page/:pathParam" component={MyPage}/>
   </Route>    
</Router>

My question is, can we declare it in one route? If I add only the second row then the route without the parameter is not found.

EDIT#1:

The solution mentioned here about the following syntax did not work for me, is it a proper one? Does it exist in the documentation?

<Route path="/product/:productName/?:urlID?" handler={SomeHandler} />

My react-router version is: 1.0.3

The edit you posted was valid for an older version of React-router (v0.13) and doesn't work anymore.

---

React Router v1, v2 and v3

Since version 1.0.0 you define optional parameters with:

<Route path="to/page(/:pathParam)" component={MyPage} />

and for multiple optional parameters:

<Route path="to/page(/:pathParam1)(/:pathParam2)" component={MyPage} />

You use parenthesis ( ) to wrap the optional parts of route, including the leading slash (/). Check out the Route Matching Guide page of the official documentation.

Note: The :paramName parameter matches a URL segment up to the next /, ?, or #. For more about paths and params specifically, read more here.

---

React Router v4 and above

React Router v4 is fundamentally different than v1-v3, and optional path parameters aren't explicitly defined in the official documentation either.

Instead, you are instructed to define a path parameter that path-to-regexp understands. This allows for much greater flexibility in defining your paths, such as repeating patterns, wildcards, etc. So to define a parameter as optional you add a trailing question-mark (?).

As such, to define an optional parameter, you do:

<Route path="/to/page/:pathParam?" component={MyPage} />

and for multiple optional parameters:

<Route path="/to/page/:pathParam1?/:pathParam2?" component={MyPage} />

Note: React Router v4 is incompatible with [tag:react-router-relay] (read more here). Use version v3 or earlier (v2 recommended) instead.

For any React Router v4 users arriving here following a search, optional parameters in a <Route> are denoted with a ? suffix.

Here's the relevant documentation:

https://reacttraining.com/react-router/web/api/Route/path-string

> path: string > > Any valid URL path that path-to-regexp understands.

    <Route path="/users/:id" component={User}/>

https://www.npmjs.com/package/path-to-regexp#optional

>Optional

Parameters can be suffixed with a question mark (?) to make the parameter optional. This will also make the prefix optional.

Simple example of a paginated section of a site that can be accessed with or without a page number.

    <Route path="/section/:page?" component={Section} />

Working syntax for multiple optional params:

<Route path="/section/(page)?/:page?/(sort)?/:sort?" component={Section} />

Now, url can be:

1. /section
2. /section/page/1
3. /section/page/1/sort/asc

for react-router V5 and above use below syntax for multiple paths

<Route
          exact
          path={[path1, path2]}
          component={component}
        />

Well since you have mentioned your react-router version as 1.0.3 you can find your solution among the previous answers.

However from React Router v6 this option has been removed as mentioned. here

Hence for React Router v6 the following :

> <Route path='/page/:friendlyName/:sort?' element={<Page/>} />

will be replaced by :

> <Route path='/page/:friendlyName/:sort' element={<Page/>} /> > > > <Route path='/page/:friendlyName/' element={<Page/>} />

or you can also use :

> <Route path="/page/:friendlyName"> > > <Route path=":sort" element={<Page />} /> > > <Route path="" element={<Page />} /> > > </Route>

As with regular parameters, declaring an optional parameter is just a matter of the path property of a Route; any parameter that ends with a question mark will be treated as optional:

<Route path="to/page/:pathParam?" component={MyPage}/>

As Sayak pointed out, optional parameters have been removed from React Router V6. The easiest solution I have found was to just make two routes. One for the url without the param and one with:

<Route path="/product/:productName/" handler={SomeHandler} />
<Route path="/product/:productName/:urlID" handler={SomeHandler} />

If you are looking to do an exact match, use the following syntax: (param)?.

Eg.

<Route path={`my/(exact)?/path`} component={MyComponent} />

The nice thing about this is that you'll have props.match to play with, and you don't need to worry about checking the value of the optional parameter:

{ props: { match: { "0": "exact" } } }