How to use a custom component with react-router route transitions?

Question

The article Confirming Navigation explains how to use a browser confirmation box in your transition hook. Fine. But I want to use my own Dialog box. If I were to use the methods

Answer 1

The core problem is that setRouteLeaveHook expects the hook function to return its result synchronously. This means you don't have the time to display a custom dialog component, wait for the user to click an option, and then return the result. So we need a way to specify an asynchronous hook. Here's a utility function I wrote:

// Asynchronous version of `setRouteLeaveHook`.
// Instead of synchronously returning a result, the hook is expected to
// return a promise.
function setAsyncRouteLeaveHook(router, route, hook) {
  let withinHook = false
  let finalResult = undefined
  let finalResultSet = false
  router.setRouteLeaveHook(route, nextLocation => {
    withinHook = true
    if (!finalResultSet) {
      hook(nextLocation).then(result => {
        finalResult = result
        finalResultSet = true
        if (!withinHook && nextLocation) {
          // Re-schedule the navigation
          router.push(nextLocation)
        }
      })
    }
    let result = finalResultSet ? finalResult : false
    withinHook = false
    finalResult = undefined
    finalResultSet = false
    return result
  })
}

Here is an example of how to use it, using vex to show a dialog box:

componentWillMount() {
  setAsyncRouteLeaveHook(this.context.router, this.props.route, this.routerWillLeave)
}
​
routerWillLeave() {
  return new Promise((resolve, reject) => {
    if (!this.state.textValue) {
      // No unsaved changes -- leave
      resolve(true)
    } else {
      // Unsaved changes -- ask for confirmation
      vex.dialog.confirm({
        message: 'There are unsaved changes. Leave anyway?' + nextLocation,
        callback: result => resolve(result)
      })
    }
  })
}