ga.ts

const URL = 'https://www.google-analytics.com/collect';

export function ga(category: string, action: string) {
  return new Promise((res) => {
    const data = {
      v: 1,
      tid: 'UA-XXXXX-Y',
      t: 'event',
      ec: category,
      ea: action,
    };

    const params = new URLSearchParams();

    Object.keys(data).forEach(key => {
      params.append(key, (data as any)[key]);
    });

    const xhr = new XMLHttpRequest();
    xhr.open('POST', URL, true);
    xhr.setRequestHeader('content-type', 'text/plain');
    xhr.send(params.toString());

    xhr.onreadystatechange = () => {
      if (xhr.readyState !== 4) return;
      res(xhr);
    };
  });
}