index.js

const core = require("@actions/core");
const github = require("@actions/github");
const { Octokit } = require("@octokit/action");

const cancelAction = async () => {
  if (core.getInput("GITHUB_TOKEN")) {
    const octokit = new Octokit();

    await octokit.actions.cancelWorkflowRun({
      ...github.context.repo,
      run_id: github.context.runId,
    });

    // Wait a maximum of 1 minute for the action to be cancelled.
    await new Promise((resolve) => setTimeout(resolve, 60000));
  }

  // If no GitHub token or timeout has passed, fail action.
  process.exit(1);
};

const runAction = async () => {
  const { payload } = github.context;
  const { comment } = payload;

  if (!comment) {
    console.log("Action triggered on non-comment event.");
    await cancelAction();
  }

  const vercel_bot_name = core.getInput("vercel_bot_name");

  if (comment.user.login !== vercel_bot_name) {
    console.log("Comment did not originate from Vercel bot.", {
      vercel_bot_name,
    });
    await cancelAction();
  }

  const cancel_on_strings = core.getInput("cancel_on_strings").split(",");

  if (cancel_on_strings.some((word) => comment.body.includes(word))) {
    console.log("Comment contained a word that should cancel the action.", {
      cancel_on_strings,
      comment: comment.body,
    });
    await cancelAction();
  }

  const preview_url_regexp = new RegExp(core.getInput("preview_url_regexp"));
  const regex_matches = comment.body.match(preview_url_regexp);

  if (!regex_matches) {
    console.log("Unable to find a preview URL in comment's body.", {
      comment: comment.body,
    });
    await cancelAction();
  }

  const vercel_preview_url = regex_matches[1];

  if (vercel_preview_url) {
    console.log("Found preview URL.", { vercel_preview_url });
    core.setOutput("vercel_preview_url", vercel_preview_url);
    process.exit(0);
  } else {
    console.log(
      "The regular expression is in an invalid format. Please ensure the first capture group caputures the preview URL."
    );
    process.exit(1);
  }
};

runAction();