React useEffect is not triggering on route change

Question

I expect that console.log('Refresh') runs every time the route changes (switching from Component1 to Component2). But it's only triggering on first render. Why?

index.js:

import React from 'react';
import ReactDOM from 'react-dom';
import App from './App';
import { BrowserRouter } from 'react-router-dom';

ReactDOM.render(<BrowserRouter><App /></BrowserRouter>, document.getElementById('root'));

App.js:

import React, { useEffect } from 'react';
import { Switch, Route } from 'react-router-dom';
import Nav from './Nav';
import Component1 from './Component1';
import Component2 from './Component2';

const App = () => {

  useEffect( () => console.log('Refresh'));

  return (
        [<Switch>
            <Route                            component = {Nav}/>
        </Switch>,
        <Switch>
            <Route exact path = '/component1' component = {Component1}/>
            <Route exact path = '/component2' component = {Component2}/>
        </Switch>]
  );
}

export default App;

Nav.js:

import React from 'react';
import { Link } from 'react-router-dom';

const  Nav = () => {
  return (
    <div>
        <Link to = '/component1'>Component 1</Link>
        <Link to = '/component2'>Component 2</Link>
    </div>
  );
}

export default Nav;

Component1.js:

import React from 'react';

const  Component1 = () => {

  return (
    <div>
        <p>Hi</p>
    </div>
  );
}

export default Component1;

Component2.js:

import React from 'react';

const  Component2 = () => {
  return (
    <div>
        <p>Bye</p>
    </div>
  );
}

export default Component2;

Where is your `````` component? – sigmus Sep 18 '19 at 06:45 — sigmus, Sep 18 '19 at 06:45
On **`index.js`** (question updated). – Erik Martín Jordán Sep 18 '19 at 08:42 — Erik Martín Jordán, Sep 18 '19 at 08:42

score 12 · Accepted Answer · answered Sep 18 '19 at 09:18

12

The useEffect is not triggered because the App component is not re-rendered, nothing changed in that component (no state or props update).

If you want the App component to re-render when the route change, you can use the withRouter HOC to inject route props, like this :

import { Switch, Route, withRouter } from 'react-router-dom';

const App = () => {

  useEffect( () => console.log('Refresh'));

  return (...);
}

export default withRouter(App);

Example : https://codesandbox.io/s/youthful-pare-n8p1y

answered Sep 18 '19 at 09:18

Mohamed Ramrami

9,559
3
29
45

1

Understood. Good answer. – Erik Martín Jordán Sep 18 '19 at 11:54
this did not resolve my issue. in my case useEffect works as expected UNTIL i navigate to a different route, and come back to current route, and then useEffect doesn't fire, seems to happen regardless of listening to specific state var or not. – Sonic Soul Aug 16 '20 at 17:44
@SonicSoul Could you open a new question with your code ? Seems like a different issue. – Mohamed Ramrami Aug 17 '20 at 10:25

score 7 · Answer 2 · answered Feb 16 '20 at 17:40

7

use the key attribute so everytime we render new component (different key)

<Route path='/mypath/:username' exact render= {routeProps =><MyCompo {...routeProps} key={document.location.href} />} />

answered Feb 16 '20 at 17:40

Aliens Dev

121
1
2

You made my day.Thanks you so much – Vishal Shori Dec 04 '20 at 16:52

score 4 · Answer 3 · answered Jun 17 '20 at 06:24

Use the 2nd argument to useEffect to conditionally apply effect. For example via react-router-dom, you get some properties

const { schoolId, classId } = props

useEffect(() => {
   // fetch something here
}, [schoolId, classId)

Here [schoolId, classId acts as the unique identifier for useEffect to trigger.

React useEffect is not triggering on route change

3 Answers3