How to access url parameter in a react component

You can access route parameter in react-router-dom v4.x, by getting params from the match props.

Where you define your routes,

import { BrowserRouter as Router, Switch, Route, Link } from 'react-router-dom';

...
<Router>
  <App>
    <Switch>
      <Route exact path="/" component={List} />
      <Route path="/:parameterToAccess" component={CustomComponent} />
    </Switch>
  </App>
</Router>
...

In your component,

class CustomComponent extends React.Component {
   constructor(props) {
     super(props);
     this.routeParam = props.match.params.parameterToAccess;
   }
}

if you use routing then you can specify your route to expect the parameter.

 <Route path='/yourpath/:ParamName' component={CustomComponent}/> 

your component needs to be wrapped in the withRouter HOC for you to access this.

 import {withRouter} from 'react-router-dom';
 class CustomComponent extends React.Component{
   constructor(props){
   }
   //**ACCESS PARAMETER VALUE LIKE THIS**
   sample(){
      let Paramvalue=this.props.match.params.ParamName;
   }   
 }
 export default withRouter(CustomComponent);

You can do it like this:

class CustomComponent extends React.Component {
    constructor({ match, ...props }) {
        console.log(match.params)
    }
}

As {match} is passed to the component as a prop(property) so we can access this prop as a normal prop way.

class CustomComponent extends React.Component {
console.log(this.props.match.url)
}

Routes

import logo from './logo.svg';
import './App.css';
import {BrowserRouter as Router,Route,Switch} from 'react-router-dom';

import UpdateEmployeeComponent from './components/UpdateEmployeeComponent';

function App() {
  return (
      <div>
        <Router>
          <div className="container">
            <Switch>
              <Route path="/update-employee/:id" component={UpdateEmployeeComponent}></Route>
            </Switch>
          </div>          
        </Router>
      </div>

  );
}

export default App;

Component

import React, { Component } from 'react';

class UpdateEmployeeComponent extends Component {
    constructor(props){
        super(props);
        this.state ={
            id : this.props.match.params.id                  
        }           
        console.log('Employee Id ::: '+this.id);
    }    

    render() {
        return (
            <div>
            
            </div>
        );
    }
}
export default UpdateEmployeeComponent;