async init()

in functions/src/plugins/common.ts [90:133]
35 lines of code
4 McCabe index (conditional complexity)

  async init(github: GitHubAPI, repositories: Repository[]): Promise<void> {
    await Promise.all(repositories.map(async repository => {
      this.robot.log(`Starting init for repository "${repository.full_name}"`);
      const [owner, repo] = repository.full_name.split('/');

      const dbPRSnapshots = await this.pullRequests
        .where('repository', '==', repository.id)
        .where('state', '==', 'open')
        .get();

      // list of existing opened PRs in the db
      const dbPRs = dbPRSnapshots.docs.map(doc => doc.id);

      const ghPRs = await github.paginate(github.pullRequests.list({
        owner,
        repo,
        state: 'open',
        per_page: 100
      }), pages => (pages as any as Github.AnyResponse).data) as Github.PullRequestsListResponse;

      ghPRs.forEach(async pr => {
        const index = dbPRs.indexOf(pr.id.toString());
        if(index !== -1) {
          dbPRs.splice(index, 1);
        }
      });

      // update the state of all PRs that are no longer opened
      if(dbPRs.length > 0) {
        const batch = this.db.batch();
        dbPRs.forEach(async id => {
          batch.set(this.pullRequests.doc(id.toString()), {state: 'closed'}, {merge: true});
        });
        batch.commit().catch(err => {
          this.robot.log.error(err);
          throw err;
        });
      }

      // add/update opened PRs
      return Promise.all(ghPRs.map(pr => github.pullRequests.get({number: pr.number, owner, repo})
        .then(res => this.updateDbPR(github, owner, repo, pr.number, repository.id, res.data))));
    }));
  }