Why doesn't Playwright reporter wait for async functions to complete?

I am using custom playwright reporter (but I think this issue is not only tied to reporter) and there in async OnTestEnd(test, result) I am trying to run exec command. With debugger turned on I see that as soon as program reaches this exec function it skips it and it ends.

const { exec } = require('child_process');

class CustomPDFReporter {
  onTestEnd(test, result) {
    const cmd = `C:\\Program Files\\wkhtmltopdf\\bin\\wkhtmltopdf.exe --quiet --print-media-type ...`;

    exec(cmd, (error, stdout, stderr) => {
      if (error) {
        console.error(`Error executing command: ${error.message}`);
        return;
      }

      if (stderr) {
        console.error(`Error output: ${stderr}`);
        return;
      }

      console.log("Generation successful!");
      console.log(`Command Output: ${stdout}`);
    });
  }
}

module.exports = CustomPDFReporter;

Above is one of many attempts to correctly run this function. But it skips all the time.

As mentioned in the comments, use execSync instead of the async callback version exec:

const {execSync} = require("child_process");

class CustomPDFReporter {
  onTestEnd(test, result) {
    const cmd = `C:\\Program Files\\wkhtmltopdf\\bin\\wkhtmltopdf.exe --quiet --print-media-type ...`;
    
    try {
      const {stdout, stderr} = execSync(cmd);

      if (stderr) {
        console.error(`Error output: ${stderr}`);
        return;
      }

      console.log("Generation successful!");
      console.log(`Command Output: ${stdout}`);
    }
    catch (error) {
      console.error(`Error executing command: ${error.message}`);
    }
  }
}

module.exports = CustomPDFReporter;

If you happened to be in an async function, you can promisify exec to avoid its callback running in a separate promise chain (shown in vanilla Node):

const {promisify} = require("util");
const exec = promisify(require("child_process").exec);

(async () => {
  try {
    const {stderr, stdout} = await exec("ls"); // or "dir" on windows

    if (stderr) {
      console.error(`Error output: ${stderr}`);
    }
    else {
      console.log("Generation successful!");
      console.log(`Command Output: ${stdout}`);
    }
  }
  catch (err) {
    console.error(`Error executing command: ${err.message}`);
  }
})();