fonthelper.js

// https://github.com/kvnang/workers-og/blob/main/packages/workers-og/src/font.ts
const fs = require("fs");
async function loadGoogleFont({ family, weight, text }) {
  const params = {
    family: `${encodeURIComponent(family)}${weight ? `:wght@${weight}` : ""}`,
  };

  if (text) {
    params.text = text;
  } else {
    params.subset = "latin";
  }

  const url = `https://fonts.googleapis.com/css2?${Object.keys(params)
    .map((key) => `${key}=${params[key]}`)
    .join("&")}`;

  let res = await fetch(`${url}`, {
    headers: {
      // construct user agent to get TTF font
      "User-Agent":
        "Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_8; de-at) AppleWebKit/533.21.1 (KHTML, like Gecko) Version/5.0.5 Safari/533.21.1",
    },
  });

  res = new Response(res.body, res);
  res.headers.append("Cache-Control", "s-maxage=3600");

  const body = await res.text();
  // Get the font URL from the CSS text
  const fontUrl = body.match(
    /src: url\((.+)\) format\('(opentype|truetype)'\)/,
  )?.[1];

  if (!fontUrl) {
    throw new Error("Could not find font URL");
  }

  return fetch(fontUrl).then((res) => res.arrayBuffer());
}