react-router/docs/Troubleshooting.md

A complete routing library for React.js

# Troubleshooting

### How to get previous path?

```js
<Route component={App}>
  {/* ... other routes */}
</Route>

const App = React.createClass({
  getInitialState() {
    return { showBackButton: false }
  },

  componentWillReceiveProps(nextProps) {
    const routeChanged = nextProps.location !== this.props.location
    this.setState({ showBackButton: routeChanged })
  }
})
```