text: // Copyright 2021 Google LLC
  //
  // Licensed under the Apache License, Version 2.0 (the "License");
  // you may not use this file except in compliance with the License.
  // You may obtain a copy of the License at
  //
  //      http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing, software
  // distributed under the License is distributed on an "AS IS" BASIS,
  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  // See the License for the specific language governing permissions and
  // limitations under the License.
  
  
  'use strict';
  
  function main(parent) {
    // [START dialogflow_v2beta1_generated_Conversations_ListMessages_async]
    /**
     * TODO(developer): Uncomment these variables before running the sample.
     */
    /**
     *  Required. The name of the conversation to list messages for.
     *  Format: `projects/<Project ID>/locations/<Location
     *  ID>/conversations/<Conversation ID>`
     */
    // const parent = 'abc123'
    /**
     *  Optional. Filter on message fields. Currently predicates on `create_time`
     *  and `create_time_epoch_microseconds` are supported. `create_time` only
     *  support milliseconds accuracy. E.g.,
     *  `create_time_epoch_microseconds > 1551790877964485` or
     *  `create_time > "2017-01-15T01:30:15.01Z"`.
     *  For more information about filtering, see
     *  API Filtering (https://aip.dev/160).
     */
    // const filter = 'abc123'
    /**
     *  Optional. The maximum number of items to return in a single page. By
     *  default 100 and at most 1000.
     */
    // const pageSize = 1234
    /**
     *  Optional. The next_page_token value returned from a previous list request.
     */
    // const pageToken = 'abc123'
  
    // Imports the Dialogflow library
    const {ConversationsClient} = require('@google-cloud/dialogflow').v2beta1;
  
    // Instantiates a client
    const dialogflowClient = new ConversationsClient();
  
    async function callListMessages() {
      // Construct request
      const request = {
        parent,
      };
  
      // Run request
      const iterable = await dialogflowClient.listMessagesAsync(request);
      for await (const response of iterable) {
          console.log(response);
      }
    }
  
    callListMessages();
    // [END dialogflow_v2beta1_generated_Conversations_ListMessages_async]
  }
  
  process.on('unhandledRejection', err => {
    console.error(err.message);
    process.exitCode = 1;
  });
  main(...process.argv.slice(2));
  