title: How to use 'this.props.params' in React?
body: <p>I send a certain id (idValue) to my component and use it like this:</p>
  
  <pre><code>componentDidMount() {
      this.onHandleFetch(this.props.params.idValue);
    }
  </code></pre>
  
  <p>But sometimes this component opens without any input parameters (without idValue) and I got this error:</p>
  
  <pre><code>TypeError: Cannot read property 'idValue' of undefined
  </code></pre>
  
  <p>How can I fix it?</p>
  
  <p>I've tried to use <em>typeof</em>, but it was unsuccessful</p>
  
  <p>In the component from which the value is transferred, I use <strong>context router</strong></p>