factory-function.ts

async function getThread(github: any, url: string): Promise<Thread> {
    let issueMatch = /api.github.com\/repos\/([\-\w]+)\/([\-\w]+)\/issues\/(\d+)/.exec(url);
    if (!issueMatch) {
        throw new Error(`Received issue notification that didn't match regex: ${url}`);
    }

    let repo = new Repo(issueMatch[1], issueMatch[2]);
    let id = parseInt(issueMatch[3], 10);

    let comments = await github.issues.getComments({
        user: repo.user,
        repo: repo.name,
        number: id
    });
    
    return new Thread(github, url, repo, id, comments);
}

class Thread {
    constructor (private github: any,
                 private url: string,
                 public repo: Repo,
                 public id: number,
                 public comments: any[]) {
    }

    comment(message: string): Promise<void> {
        return this.github.issues.createComment({
            user: this.repo.user,
            repo: this.repo.name,
            number: this.id,
            body: message
        });
    }
}