Get the base url to a react router route handler.

example.js

import React from 'react'
import { Link } from 'react-router'
import getRouteHandlerBaseUrl from 'js/helpers/get-route-handler-base-url'

class Something extends React.Component {
	
	componentWillMount() {
		this._baseUrl = getRouteHandlerBaseUrl(this.props)
	}

	render() {
		return (
			<div>
				<Link to={this._baseUrl+"/something-else"}>Link to [url to this handler]/something-else</Link>
			</div>
		)
	}
}

export default Something

get-route-handler-base-url.js

// calculate the base url for a router handler from the props the router provides to it
export default function(props) {
	if (!props.route || !props.routes || !props.location) {
		throw new Error("Missing props from React router.")
	}
	var route = props.route
	var routeDepth = props.routes.indexOf(route)
	return props.location.pathname.split("/").slice(0, routeDepth+1).join("/")
}