catch exceptions in async computations

run-command.js

function* runCommand({
  pkg,
  command,
  cwd,
  pkgPath,
  log = `running command for ${pkg}`,
}) {
  try {
    yield function*() {
      console.log(log);
      let response = "";
      let child = yield ChildProcess.spawn(command, [], {
        cwd: path.join(cwd, pkgPath),
        shell: process.env.shell || true,
        stdio: "pipe",
        windowsHide: true,
      });
      yield throwOnErrorEvent(child);
      let resEvents = yield on(child.stdout, "data");
      while (response === "" || response === "undefined") {
        try {
          let data = yield resEvents.next();
          response += !data.value
            ? data.toString().trim()
            : data.value.toString().trim();
        } catch (e) {}
      }
      const exit = yield once(child, "exit");
      if (exit[1] !== null) {
        console.log(exit);
        throw { value: exit[0], message: exit[1] };
      }
      return response;
    }
  } catch (error) {
    //if `child` fails, the error can be caught here.
  }

};