Pass React Strict Tests

[dstroot]

Version

"react-router-dom": "^4.3.1"

Test Case

Enable React Strict Mode - View console

Warning: Unsafe lifecycle methods were found within a strict-mode tree:

componentWillMount: Please update the following components to use componentDidMount instead: BrowserRouter, Route, Router, SideEffect(NullComponent), Switch, t

componentWillReceiveProps: Please update the following components to use static getDerivedStateFromProps instead: Route, Router, Switch

componentWillUpdate: Please update the following components to use componentDidUpdate instead: t

Learn more about this warning here:
https://fb.me/react-strict-mode-warnings

Steps to reproduce

Enable React Strict Mode - View console

Expected Behavior

Passes React Strict Mode

Actual Behavior

Does not pass React Strict Mode

[timdorr]

This is already done on master. You can use the 4.4 betas or wait for a final release.

[timdorr]

See #6060 and #6385