function main(projectId, location, agentId, event, languageCode) {
  // [START dialogflow_cx_v3_detect_intent_event_input_async]
  /**
   * TODO(developer): Uncomment these variables before running the sample.
   */
  /**
   *  Required. The name of the session this query is sent to.
   *  Format: `projects/<Project ID>/locations/<Location ID>/agents/<Agent
   *  ID>/sessions/<Session ID>` or `projects/<Project ID>/locations/<Location
   *  ID>/agents/<Agent ID>/environments/<Environment ID>/sessions/<Session ID>`.
   *  If `Environment ID` is not specified, we assume default 'draft'
   *  environment.
   *  It's up to the API caller to choose an appropriate `Session ID`. It can be
   *  a random number or some type of session identifiers (preferably hashed).
   *  The length of the `Session ID` must not exceed 36 characters.
   *  For more information, see the sessions
   *  guide (https://cloud.google.com/dialogflow/cx/docs/concept/session).
   *  Note: Always use agent versions for production traffic.
   *  See Versions and
   *  environments (https://cloud.google.com/dialogflow/cx/docs/concept/version).
   */

  /**
   * Optional. The parameters of this query.
   */
  // const queryParams = {}
  /**
   *  Required. The input specification. See https://cloud.google.com/dialogflow/cx/docs/reference/rest/v3beta1/ConversationTurn#QueryInput for information about query inputs.
   */
  // const event = 'name-of-event-to-trigger';

  // Imports the Cx library
  const {SessionsClient} = require('@google-cloud/dialogflow-cx');
  /**
   * Example for regional endpoint:
   *   const location = 'us-central1'
   *   const client = new SessionsClient({apiEndpoint: 'us-central1-dialogflow.googleapis.com'})
   */
  // Instantiates a client
  const cxClient = new SessionsClient();

  async function detectIntentWithEventInput() {
    const sessionId = Math.random().toString(36).substring(7);
    const sessionPath = cxClient.projectLocationAgentSessionPath(
      projectId,
      location,
      agentId,
      sessionId
    );

    // Construct detect intent request
    const request = {
      session: sessionPath,
      queryInput: {
        event: {
          event: event,
        },
        languageCode,
      },
    };

    // Send request and receive response
    const [response] = await cxClient.detectIntent(request);
    console.log(`Event Name: ${event}`);

    // Response message from the triggered event
    console.log('Agent Response: \n');
    console.log(response.queryResult.responseMessages[0].text.text[0]);
  }

  detectIntentWithEventInput();
  // [END dialogflow_cx_v3_detect_intent_event_input_async]
}
Detects intent using EventInput

See https://cloud.google.com/dialogflow/cx/docs/quick/api before running the code snippet.