For SUSI Web Chat, I needed a query parameter which can be passed to the components directly to activate the SUSI dreams in my textarea using just the URL which is not easy when one is using react-router. React URL Query is a package for managing state through query parameters in the URL in React. It integrates well with React Router and Redux and provides additional tools specifically targeted at serializing and deserializing state in URL query parameters. So for example, if one wants to pass some parameters to populate in your component directly through the URL, you can use react-url-query. Eg. http://chat.susi.ai/?dream=fossasia will populate fossasia in our textarea section without actually typing the term textarea.

So this in the URL,

Will produce this in the textarea,

To achieve this. the following steps are required:

1. First we proceed with installing the packages (Dependencies  – history)

npm install history --save

npm install react-url-query --save

2.   We then instantiate a history in our component where we want to listen to the parameters like the following code. Our class ChatApp is where we want to pass the params.

ChatApp.react.js

import history from '../history'; 
//Import the history object from the History package.
    
 // force an update if the URL changes inside the componentDidMount function
  componentDidMount() {
      history.listen(() => this.forceUpdate());
   }

3.  Next, we define the props of the parameters in our Message Section. For that we need the following props-

• urlPropsQueryConfig – this is where we define our URLConfig
• Static proptypes – the query param to which we want to pass the value, so for me it’s dream.
• The defaultProps when no such value is being passed to our param should be left a blank.
• And then we finally assign the props.
• This is then passed to the Message Composer Section from where we receive the value passed.

MessageSection.react.js

// Adding the UrlConfig
const urlPropsQueryConfig = {
  dream: { type: UrlQueryParamTypes.string }
};

 // Defining the query param inside our ClassName
  static propTypes = {
    dream: PropTypes.string
  }
// Setting the default param

  static defaultProps = {     
dream: ''
  }

 //Assigning the props inside the render() function
    const {
      dream
    } = this.props;
 //Passing the dream to the MessageComposer Section

                  <MessageComposer
                    threadID={this.state.thread.id}
                    theme={this.state.darkTheme}
                    dream={dream} />                
//Exporting our Class

export default addUrlProps({ urlPropsQueryConfig })(ClassName);

4. Next we update the Message Composer section by the props we had passed. For this we first check if the props are null, we don’t populate it in our textarea if it is, otherwise we populate the textarea with the value ‘dream + props.dream’ so the value passed in the URL will be prepend by a word dream to enable the ‘dream value’ in our textarea.

The full file is available at MessageComposer.js

 //Add Check to the constructor
 constructor(props) {
    super(props);
    this.state = {text: ''};
    if(props.dream!==''){   //Setting the text as received ‘dream dreamPassed’
      this.state= {text: 'dream '+ props.dream}
    }
  }
// Populate the textarea
        <textarea
          name="message"
          value={this.state.text}
          onChange={this._onChange.bind(this)}
          onKeyDown={this._onKeyDown.bind(this)}
          ref={(textarea)=> { this.nameInput = textarea; }}
          placeholder="Type a message..."
        />
// Add props to the component
MessageComposer.propTypes = {
  /* other props */,
  dream: PropTypes.string //Setting Proptypes to receive the prop from the MessageSection
};

Now we have the full code working for querying any dream. Head over to chat.susi.ai?dream=fossasia Change fossasia to see the text change.

Resources

• React URL Query
• Examples – https://github.com/pbeshai/react-url-query/tree/master/examples/basic/src
• Official Repository – https://github.com/pbeshai/react-url-query/