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Adds back in `useBlocker` and `usePrompt` to `react-router-dom` version 6.0.2 (they removed after the 6.0.0 beta, temporarily)
* These hooks re-implement the now removed useBlocker and usePrompt hooks in 'react-router-dom'.
* Thanks for the idea @piecyk
* Source:
import { useContext, useEffect, useCallback } from 'react';
import { UNSAFE_NavigationContext as NavigationContext } from 'react-router-dom';
* Blocks all navigation attempts. This is useful for preventing the page from
* changing until some condition is met, like saving form data.
* @param blocker
* @param when
* @see
export function useBlocker( blocker, when = true ) {
const { navigator } = useContext( NavigationContext );
useEffect( () => {
if ( ! when ) return;
const unblock = navigator.block( ( tx ) => {
const autoUnblockingTx = {
retry() {
// Automatically unblock the transition so it can play all the way
// through before retrying it. TODO: Figure out how to re-enable
// this block if the transition is cancelled for some reason.
blocker( autoUnblockingTx );
} );
return unblock;
}, [ navigator, blocker, when ] );
* Prompts the user with an Alert before they leave the current screen.
* @param message
* @param when
export function usePrompt( message, when = true ) {
const blocker = useCallback(
( tx ) => {
// eslint-disable-next-line no-alert
if ( window.confirm( message ) ) tx.retry();
[ message ]
useBlocker( blocker, when );
const MyComponent = () => {
const formIsDirty = true; // Condition to trigger the prompt.
usePrompt( 'Leave screen?', formIsDirty );
return (
<div>Hello world</div>
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onionhammer commented Dec 28, 2021

Would be cool if this would only prompt if 'MyComponent was no longer going to be rendered as a result of continuing - for example, you could be navigating a child component, leaving the form completely intact

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AdnanTheExcellent commented Jan 3, 2022

i am getting a TS2339: Property 'block' does not exist on type 'Navigator'. error when using typescript.

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WhiteYaksha commented Jan 5, 2022

@AdnanTheExcellent It seems like it's a typescript issue, you need to add "block" to the interface definition here


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hackerghost93 commented Jan 18, 2022

@WhiteYaksha so to add this i need to fork the repo and add this manually?

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jsmcconkey commented Mar 25, 2022

@hackerghost93 - I'm sure you got this sorted out by now, but I used patch package myself. If you install patch-package you can make the fix. Then you can run the patch-package tool. Then whenever your modules are installed the patch will then be applied. you can read more about his package at the following link.

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leminhhung-NamiQ commented Mar 28, 2022

it's not the best way to do, who else has another way, of change node modules it will fail, please help, thanks

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jsmcconkey commented Mar 28, 2022

@leminhhung-NamiQ that is highly dependent on the type of change that you do to the node module and the context of that change.

From my point of view this is a small change to a type interface applied to a specific version of a the react-router module. Yes, at some point in the future this patch might fail, however, the risk is minimal. The way I see it at the moment is you can:

  1. Update the type interface through patching the package.
  2. Ignore the type error for now.
  3. Fork the repo and make the change yourself.

If you plan to fork the repo you might as well patch the package. If you lock your node module to a specific version and then watch for updates to react router you should be fine. Based upon this comment it would appear the intention is to bring "block" back.

remix-run/react-router#8139 (comment)

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julix-unity commented Apr 8, 2022

Can't you just extend the type and use as?

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matrey commented May 2, 2022

There is a working Typescript version here:

import { History, Transition } from 'history';
  • tx is a Transition
  • as for navigator:
type ExtendNavigator = Navigator & Pick<History, "block">;
const unblock = (navigator as any as ExtendNavigator).block(...

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zwilderrr commented May 25, 2022

What's the issue with this approach? Meaning, why isn't this a part of v6?

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Ralfarios commented May 29, 2022

I do exactly the same like this code, but I still moved to other routes even cancel button clicked. :/

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mknospe commented Aug 4, 2022

Works like a charm. Thanks for sharing! 💯

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borstelmannl commented Sep 19, 2022

if i use this workaround:
i receive an exception: navigator.block is not a function. Anyone else having this issue?

i am using the newest react router version 6.4

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matrey commented Sep 19, 2022

You can check the original github issue that led to the creation of this gist: remix-run/react-router#8139 (comment)

Just fyi, it's still possible to use navigator.block via history package with v6.4.0, by replacing BrowserRouter with unstable_HistoryRouter

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fcmdvtk4r commented Sep 27, 2022

Resetting any of the dependencies at line 38 when canceling the navigation solved the TODO for me.

Thanks for sharing!

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