How to use the @elastic/app-search-javascript.createClient function in @elastic/app-search-javascript

searchKey,
    engineName,
    hostIdentifier,
    beforeSearchCall = (queryOptions, next) => next(queryOptions),
    beforeAutocompleteResultsCall = (queryOptions, next) => next(queryOptions),
    beforeAutocompleteSuggestionsCall = (queryOptions, next) =>
      next(queryOptions),
    endpointBase = ""
  }) {
    if (!engineName || !(hostIdentifier || endpointBase) || !searchKey) {
      throw Error(
        "hostIdentifier or endpointBase, engineName, and searchKey are required"
      );
    }

    this.client = ElasticAppSearch.createClient({
      ...(endpointBase && { endpointBase }), //Add property on condition
      ...(hostIdentifier && { hostIdentifier: hostIdentifier }),
      apiKey: searchKey,
      engineName: engineName,
      additionalHeaders: {
        "x-swiftype-integration": "search-ui",
        "x-swiftype-integration-version": version
      }
    });
    this.beforeSearchCall = beforeSearchCall;
    this.beforeAutocompleteResultsCall = beforeAutocompleteResultsCall;
    this.beforeAutocompleteSuggestionsCall = beforeAutocompleteSuggestionsCall;
  }