normalize-paginated-list-response.ts

/**
 * Some “list” response that can be paginated have a different response structure
 *
 * They have a `total_count` key in the response (search also has `incomplete_results`,
 * /installation/repositories also has `repository_selection`), as well as a key with
 * the list of the items which name varies from endpoint to endpoint.
 *
 * Octokit normalizes these responses so that paginated results are always returned following
 * the same structure. One challenge is that if the list response has only one page, no Link
 * header is provided, so this header alone is not sufficient to check wether a response is
 * paginated or not.
 *
 * We check if a "total_count" key is present in the response data, but also make sure that
 * a "url" property is not, as the "Get the combined status for a specific ref" endpoint would
 * otherwise match: https://developer.github.com/v3/repos/statuses/#get-the-combined-status-for-a-specific-ref
 */

import { OctokitResponse } from "./types";

export function normalizePaginatedListResponse(
  response: OctokitResponse<any>
): OctokitResponse<any> {
  const responseNeedsNormalization =
    "total_count" in response.data && !("url" in response.data);
  if (!responseNeedsNormalization) return response;

  // keep the additional properties intact as there is currently no other way
  // to retrieve the same information.
  const incompleteResults = response.data.incomplete_results;
  const repositorySelection = response.data.repository_selection;
  const totalCount = response.data.total_count;
  delete response.data.incomplete_results;
  delete response.data.repository_selection;
  delete response.data.total_count;

  const namespaceKey = Object.keys(response.data)[0];
  const data = response.data[namespaceKey];
  response.data = data;

  if (typeof incompleteResults !== "undefined") {
    response.data.incomplete_results = incompleteResults;
  }

  if (typeof repositorySelection !== "undefined") {
    response.data.repository_selection = repositorySelection;
  }

  response.data.total_count = totalCount;
  return response;
}