Add <Forward /> to API

[du5rte]

Often you redirect a route, as your application gets more complex and you require params and search on that route you find after hours of debugging that <Redirect /> strips everything away #4919. I propose a <Forward /> to explicitly say pass everything over, here's my current solution to this problem.

class Forward extends React.Component {
  forwardParams(to, computedMatch) {
    const paramKeys = Object.keys(computedMatch.params);

    const replacedParamsKeys = paramKeys.reduce((url, key) => (
      url.replace(`:${key}`, computedMatch.params[key])
    ), to);

    return replacedParamsKeys;
  }

  render() {
    const { to, computedMatch, location, ...props } = this.props;

    return (
      <Redirect
        to={{
          state: { from: location },
          pathname: this.forwardParams(to, computedMatch),
          search: location.search,
        }}
        {...props}
      />
    );
  }
}

Example usecase redirecting a authentication callback

<Forward from="/callback" to="/oauth/callback" />

[timdorr]

This is already in 4.3.0-rc.2. It's on react-router@next.