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React router doesn't update sub components params

In my React application, I have trouble making a sub-component update based on props.
the sub-component gets the props from a <Link/> tag that is exposed to store state
const CallPortfolioManagement= (props) => {
const { portfolio } = props;
return (
<div>
<Link
to={{pathname: `/portfolios/${portfolio.name}`,state: { portfolio: portfolio},}}>
{portfolio.name}</Link>
</div>
);
};
const mapStateToProps = (state) => {
return {
portfolio: getPortfolio(state),
};
};
export default connect(mapStateToProps)(CallPortfolioManagemnt);
the PortfolioManagement component is:
const PortfolioManagement = (props) => {
const portfolio = useLocation().state.portfolio;
return (
<>
{portfolio.stocks.map((stock, index) => (
<div key={stock.symbol}>
<h1>
{stock.symbol}
</h1>
</div>
))}
</>
);
};
export default PortfolioManagement;
a component that got a direct subscription to the state and rerenders when a new stock symbol is added:
const RenderLastStock= (props) => {
const renderLast () => {
var stocks;
if (props.portfolio) {
stocks = props.portfolio["stocks"];
return <button>{stocks[stocks.length - 1]].symbol}</button>;
}
};
return (
<>
renderLast ()}
</>
);
};
const mapStateToProps = (state) => {
return { tasks: getLoadingTasks(state), portfolios: getPortfolios(state) };
};
export default connect(mapStateToProps)(RenderLastStock);
the route declared here and calls PortfolioManagement when clicked:
function App(props) {
useEffect(() => {
props.getPortfolios();
}, []);
return (
<Router>
<div className="App">
<Switch>
<PrivateRoute>
<Route path="/portfolios/:id" component={PortfolioManagement} />
</PrivateRoute>
</Switch> </div>
</Router>
);
}
the problem is that PortfolioManagement gets the params but does no rerender when the state is changed - when I add stock symbols.
I update the store's state with Object.assign and other components that are subscribed to this state do rerender! (so there aren't any immutability problems)
looking in the redux devtools I can see the state is updated correctly, I suspect that PortfolioManagement does not rerender because react does not refer to Link's Params as props and does not know it should trigger a rerender.
please help:(

instead of using useLocation, you can use withRouter at PortfolioManagement -
import { withRouter } from 'react-router-dom'
const PortfolioManagement = (props) => {
console.log(props.location && props.location.state)
...rest code...
}
export default withRouter(PortfolioManagement);
I know its hacky, but anyhow now state comes from props and component will re-render
Edit
The usage of Link and the state location object you can send with, works on a way that the context won't be exist if the component wasn't called through the link, consider send the props through regular props at Router decoration (that I assuming is a component connected to redux store)
<Route path="/portfolios/:id" render={()=> <PortfolioManagement props={...props} />} />

didn't find a solution with react router, I solved it by cheating and giving portfolioManagement direct access to the store

How can I change this class base higher order component into a functional component?

I have already created a HOC in my react app following this, and its working fine. However i was wondering if there is a way to create a HOC as functional component(With or without state)??? since the given example is a class based component.
Tried to find the same over web but couldn't get anything. Not sure if thats even possible?? Or right thing to do ever??
Any leads will be appreciated :)

I agree with siraj, strictly speaking the example in the accepted answer is not a true HOC. The distinguishing feature of a HOC is that it returns a component, whereas the PrivateRoute component in the accepted answer is a component itself. So while it accomplishes what it set out to do just fine, I don't think it is a great example of a HOC.
In the functional component world, the most basic HOC would look like this:
const withNothing = Component => ({ ...props }) => (
<Component {...props} />
);
Calling withNothing returns another component (not an instance, that's the main difference), which can then be used just like a regular component:
const ComponentWithNothing = withNothing(Component);
const instance = <ComponentWithNothing someProp="test" />;
One way to use this is if you want to use ad-hoc (no pun intended lol) context providers.
Let's say my application has multiple points where a user can login. I don't want to copy the login logic (API calls and success/error messages) across all these points, so I'd like a reusable <Login /> component. However, in my case all these points of login differ significantly visually, so a reusable component is not an option. What I need is a reusable <WithLogin /> component, which would provide its children with all the necessary functionality - the API call and success/error messages. Here's one way to do this:
// This context will only hold the `login` method.
// Calling this method will invoke all the required logic.
const LoginContext = React.createContext();
LoginContext.displayName = "Login";
// This "HOC" (not a true HOC yet) should take care of
// all the reusable logic - API calls and messages.
// This will allow me to pass different layouts as children.
const WithLogin = ({ children }) => {
const [popup, setPopup] = useState(null);
const doLogin = useCallback(
(email, password) =>
callLoginAPI(email, password).then(
() => {
setPopup({
message: "Success"
});
},
() => {
setPopup({
error: true,
message: "Failure"
});
}
),
[setPopup]
);
return (
<LoginContext.Provider value={doLogin}>
{children}
{popup ? (
<Modal
error={popup.error}
message={popup.message}
onClose={() => setPopup(null)}
/>
) : null}
</LoginContext.Provider>
);
};
// This is my main component. It is very neat and simple
// because all the technical bits are inside WithLogin.
const MyComponent = () => {
const login = useContext(LoginContext);
const doLogin = useCallback(() => {
login("a#b.c", "password");
}, [login]);
return (
<WithLogin>
<button type="button" onClick={doLogin}>
Login!
</button>
</WithLogin>
);
};
Unfortunately, this does not work because LoginContext.Provider is instantiated inside MyComponent, and so useContext(LoginContext) returns nothing.
HOC to the rescue! What if I added a tiny middleman:
const withLogin = Component => ({ ...props }) => (
<WithLogin>
<Component {...props} />
</WithLogin>
);
And then:
const MyComponent = () => {
const login = useContext(LoginContext);
const doLogin = useCallback(() => {
login("a#b.c", "password");
}, [login]);
return (
<button type="button" onClick={doLogin}>
Login!
</button>
);
};
const MyComponentWithLogin = withLogin(MyComponent);
Bam! MyComponentWithLogin will now work as expected.
This may well not be the best way to approach this particular situation, but I kinda like it.
And yes, it really is just an extra function call, nothing more! According to the official guide:
HOCs are not part of the React API, per se. They are a pattern that emerges from React’s compositional nature.

Definitely you can create a functional stateless component that accepts component as an input and return some other component as an output, for example;
You can create a PrivateRoute component that accepts a Component as a prop value and returns some other Component depending on if user is authenticated or not.
If user is not authenticated(read it from context store) then you redirect user to login page with <Redirect to='/login'/>else you return the component passed as a prop and send other props to that component <Component {...props} />
App.js
const App = () => {
return (
<Switch>
<PrivateRoute exact path='/' component={Home} />
<Route exact path='/about' component={About} />
<Route exact path='/login' component={Login} />
<Route exact path='/register' component={Register} />
</Switch>
);
}
export default App;
PrivateRoute.jsx
import React, { useContext , useEffect} from 'react';
import { Route, Redirect } from 'react-router-dom'
import AuthContext from '../../context/auth/authContext'
const PrivateRoute = ({ component: Component, ...rest }) => {
const authContext = useContext(AuthContext)
const { loadUser, isAuthenticated } = authContext
useEffect(() => {
loadUser()
// eslint-disable-next-line
}, [])
if(isAuthenticated === null){
return <></>
}
return (
<Route {...rest} render={props =>
!isAuthenticated ? (
<Redirect to='/login'/>
) : (
<Component {...props} />
)
}
/>
);
};
export default PrivateRoute;
Higher Order Components does not have to be class components, their purpose is to take a Component as an input and return a component as an output according to some logic.

The following is an over simplified example of using HOC with functional components.
The functional component to be "wrapped":
import React from 'react'
import withClasses from '../withClasses'
const ToBeWrappedByHOC = () => {
return (
<div>
<p>I'm wrapped by a higher order component</p>
</div>
)
}
export default withClasses(ToBeWrappedByHOC, "myClassName");
The Higher Order Component:
import React from 'react'
const withClasses = (WrappedComponent, classes) => {
return (props) => (
<div className={classes}>
<WrappedComponent {...props} />
</div>
);
};
export default withClasses;
The component can be used in a different component like so.
<ToBeWrappedByHOC/>

I might be late to the party but here is my two-cent regarding the HOC
Creating HOC in a true react functional component way is kind of impossible because it is suggested not to call hook inside a nested function.
Don’t call Hooks inside loops, conditions, or nested functions. Instead, always use Hooks at the top level of your React function, before any early returns. By following this rule, you ensure that Hooks are called in the same order each time a component renders. That’s what allows React to correctly preserve the state of Hooks between multiple useState and useEffect calls. (If you’re curious, we’ll explain this in-depth below.)
Rules of Hooks
Here is what I have tried and failed
import React, { useState } from "react";
import "./styles.css";
function Component(props) {
console.log(props);
return (
<div>
<h2> Component Count {props.count}</h2>
<button onClick={props.handleClick}>Click</button>
</div>
);
}
function Component1(props) {
console.log(props);
return (
<div>
<h2> Component1 Count {props.count}</h2>
<button onClick={props.handleClick}>Click</button>
</div>
);
}
function HOC(WrapperFunction) {
return function (props) {
const handleClick = () => {
setCount(count + 1);
};
const [count, setCount] = useState(0);
return (
<WrapperFunction handleClick={handleClick} count={count} {...props} />
);
}
}
const Comp1 = HOC((props) => {
return <Component {...props} />;
});
const Comp2 = HOC((props) => {
return <Component1 {...props} />;
});
export default function App() {
return (
<div className="App">
<Comp1 name="hel" />
<Comp2 />
</div>
);
}
CodeSandBox
Even though the code works in codesandbox but it won't run in your local machine because of the above rule, you should get the following error if you try to run this code
React Hook "useState" cannot be called inside a callback
So to go around this I have done the following
import "./styles.css";
import * as React from "react";
//macbook
function Company(props) {
return (
<>
<h1>Company</h1>
<p>{props.count}</p>
<button onClick={() => props.increment()}>increment</button>
</>
);
}
function Developer(props) {
return (
<>
<h1>Developer</h1>
<p>{props.count}</p>
<button onClick={() => props.increment()}>increment</button>
</>
);
}
//decorator
function HOC(Component) {
// return function () {
// const [data, setData] = React.useState();
// return <Component />;
// };
class Wrapper extends React.Component {
constructor(props) {
super(props);
this.state = { count: 0 };
}
handleClick = () => {
this.setState({ count: this.state.count + 1 });
};
render() {
return (
<Component count={this.state.count} increment={this.handleClick} />
);
}
}
return Wrapper;
}
const NewCompany = HOC(Company);
const NewDeveloper = HOC(Developer);
export default function App() {
return (
<div className="App">
<NewCompany name={"Google"} />
<br />
<NewDeveloper />
</div>
);
}
CodeSandbox

I think for functional component this works fine
import {useEffect, useState} from 'react';
// Target Component
function Clock({ time }) {
return <h1>{time}</h1>
}
// HOC
function app(C) {
return (props) => {
const [time, setTime] = useState(new Date().toUTCString());
useEffect(() => {
setTimeout(() => setTime(new Date().toUTCString()), 1000);
})
return <C {...props} time={time}/>
}
}
export default app(Clock);
You can test it here: https://codesandbox.io/s/hoc-s6kmnv

Yes it is possible
import React, { useState } from 'react';
const WrapperCounter = OldComponent =>{
function WrapperCounter(props){
const[count,SetCount] = useState(0)
const incrementCounter = ()=>{
SetCount(count+1)
}
return(<OldComponent {...props} count={count} incrementCounter={incrementCounter}></OldComponent>)
}
return WrapperCounter
}
export default WrapperCounter
import React from 'react';
import WrapperCounter from './WrapperCounter';
function CounterFn({count,incrementCounter}){
return(
<button onClick={incrementCounter}>Counter inside functiona component {count}</button>
)
}
export default WrapperCounter(CounterFn)

Why is my React component mounting after each action?

I have a React component called Home which is calling an action to fetch some groups when the component mounts.
I am calling an action as follows:
componentDidMount() {
const { fetchRecentGroups } = this.props;
fetchRecentGroups();
}
My reducer is picking up each action perfectly fine and is returning a state as follows:
switch(action.type) {
case REQUEST_GROUPS:
return {
...state,
loadState: FETCHING
};
case REQUEST_GROUPS_SUCCESS:
return {
...state,
loadState: SUCCESS,
groups: action.data.groups,
totalResults: action.data.totalResults
};
default:
return state;
}
I am also using the connect HOC on this component as follows:
const mapStateToProps = (state) => {
return {}
}
const mapDispatchToProps = (dispatch) => {
return {
fetchRecentGroups: () => {
dispatch(actions.fetchRecentGroups())
}
}
}
export default connect(
mapStateToProps,
mapDispatchToProps
)(Home);
The Home component is placed inside a Route like this:
<Route
exact={true}
path="/"
component={Home}
/>
My problem is that each time the reducer returns a state, the componentDidMount is called again and again in a loop. I would expect the mount to happen only once at the first load.
If I put componentDidUpdate and componentWillReceiveProps functions in my component, they are never called (only componentDidMount) so I am not able to compare props.
Does anyone know why this may be happening?
EDIT:
I have found my problem to be caused by this piece of code in my route:
const RouteBlock = () => {
if(errorSettings) {
return <Error {...errorSettings} />
}
return (
<div className={styles.RouteBlock}>
<Route exact={true} path="/" component={Home} />
<Route path="/search" render={() => <div>SEARCH</div>} />
</div>
);
};
return <Router><RouteBlock /></Router>
I changed it to:
return <Router>{RouteBlock()}</Router>

Every time you render your component, you are immediately calling function that is setting new state and you are triggering re-rendering of your component. Maybe you should use shouldComponentUpdate life cycle method that will check is your old state the same as new one.
Check out official docs: https://reactjs.org/docs/react-component.html#shouldcomponentupdate

Prevent browser from making the same async calls as the server

I am following this tutorial: https://crypt.codemancers.com/posts/2017-06-03-reactjs-server-side-rendering-with-router-v4-and-redux/ which i think is the 'standard' way of doing server side rendering in react (?).
Basically what happens is i use react router (v4) to make a tree of all the components that are about to get rendered:
const promises = branch.map(({ route }) => {
return route.component.fetchInitialData
? route.component.fetchInitialData(store.dispatch)
: Promise.resolve();
});
Wait for all those promises to resolve and then call renderToString.
In my components i have a static function called fetchInitialData which looks like this:
class Users extends React.Component {
static fetchInitialData(dispatch) {
return dispatch(getUsers());
}
componentDidMount() {
this.props.getUsers();
}
render() {
...
}
}
export default connect((state) => {
return { users: state.users };
}, (dispatch) => {
return bindActionCreators({ getUsers }, dispatch);
})(Users);
And all this works great except that getUsers is called both on the server and the client.
I could of course check if any users are loaded and not call getUsers in componentDidMount but there must be a better, explicit way to not make the async call twice.

After getting more and more familiar with react i feel fairly confident i have a solution.
I pass a browserContext object along all rendered routes, much like staticContext on the server. In the browserContext i set two values; isFirstRender and usingDevServer. isFirstRender is only true while the app is rendered for the first time and usingDevServer is only true when using the webpack-dev-server.
const store = createStore(reducers, initialReduxState, middleware);
The entry file for the browser side:
const browserContext = {
isFirstRender: true,
usingDevServer: !!process.env.USING_DEV_SERVER
};
const BrowserApp = () => {
return (
<Provider store={store}>
<BrowserRouter>
{renderRoutes(routes, { store, browserContext })}
</BrowserRouter>
</Provider>
);
};
hydrate(
<BrowserApp />,
document.getElementById('root')
);
browserContext.isFirstRender = false;
USING_DEV_SERVER is defined in the webpack config file using webpack.DefinePlugin
Then i wrote a HOC component that uses this information to fetch initial data only in situations where it is needed:
function wrapInitialDataComponent(Component) {
class InitialDatacomponent extends React.Component {
componentDidMount() {
const { store, browserContext, match } = this.props;
const fetchRequired = browserContext.usingDevServer || !browserContext.isFirstRender;
if (fetchRequired && Component.fetchInitialData) {
Component.fetchInitialData(store.dispatch, match);
}
}
render() {
return <Component {...this.props} />;
}
}
// Copy any static methods.
hoistNonReactStatics(InitialDatacomponent, Component);
// Set display name for debugging.
InitialDatacomponent.displayName = `InitialDatacomponent(${getDisplayName(Component)})`;
return InitialDatacomponent;
}
And then the last thing to do is wrap any components rendered with react router with this HOC component. I did this by simply iterating over the routes recursively:
function wrapRoutes(routes) {
routes.forEach((route) => {
route.component = wrapInitialDataComponent(route.component);
if (route.routes) {
wrapRoutes(route.routes);
}
});
}
const routes = [ ... ];
wrapRoutes(routes);
And that seems to do the trick :)

Setup react route to use URL parameters and props' function

I've got a parent component with react-router, setup like this :
constructor(props){
super(props);
this.state = {
diner: false
};
this.updateFromInvite = this.updateFromInvite.bind(this);
}
updateFromInvite(Souper) {
this.setState({diner: Souper});
}
I can't figure out how to setup the route to have both URL parameters and be able to pass a function to update the parent's state from the children component...
<Route path="/Invitation/:NomParam1?/:NomParam2?"
component = {() => (<Invitation updateApp = {this.updateFromInvite} />)} />
I think it's the closest I got...
From children's component :
class Invite extends Component {
constructor(props){
super(props);
this.state = {
diner: this.props.match.params.NomParam1 ,
JSONInfo: this.props.match.params.NomParam2
};
}
componentDidMount() {
const { diner } = this.state;
const { JSONInfo } = this.state;
const { updateApp } = this.props;
updateApp(diner);
}
render() {
return (
<div className="Invite">
<div className="col-centered">
<VidPlay/>
</div>
</div>
);
}
}
export default Invite;

The component property of the route takes a component Class, not an instance of the component. I believe you are looking to use the render property, which takes a rendered component. Your visual component shouldn't be concerned with the routing details, so you can pass that in in the Route configuration like so:
<Route path="/Invitation/:NomParam1?/:NomParam2?"
render={({match}) => (
<Invitation
updateApp={this.updateFromInvite}
diner={match.params.NomParam1}
JSONInfo={match.params.NomParam2}
/>
)}
/>
Then, in the component, don't utilize state, as that's not really what it is for:
class Invite extends Component {
componentDidMount() {
const { diner, JSONInfo, updateApp } = this.props;
// Not exactly sure what is going on here... how you
// will use JSONInfo, etc
updateApp(diner);
}
render() {
return (
<div className="Invite">
<div className="col-centered">
<VidPlay/>
</div>
</div>
);
}
}
Also, I'm not exactly sure what the parent component is doing, and why it is passing both the route params and the function down to the child, only to have the child call it back... but that is probably out of the scope of the question.
Enjoy!

If finally got it (thanks to that answer and the official documentation):
I needed to add props as parameter of my render and
use it with {...props} inside the children element!
<Route path="/Invitation/:NomParam1?/:NomParam2?"
render={ (props) =>
(<Invitation updateApp = {this.updateFromInvite} {...props} />)
}
/>
With that, I have access to BOTH :
my custom props
generic props (match, location and history)