"use strict";

const fs = require("fs");
const path = require("path");

function relative(loc) {
  return path.join(__dirname, "..", loc);
}

const builtIns = require("babel-preset-env/data/built-ins.json");
const polyfills = Object.keys(builtIns);

polyfills.concat([
  "web.timers",
  "web.immediate",
  "web.dom.iterable"]
).forEach((polyfill) => {
  fs.writeFileSync(relative(`src/core-js/modules/${polyfill}.js`), `require("core-js/modules/${polyfill}");`);
});

fs.writeFileSync(relative("src/regenerator-runtime/runtime.js"), "require(\"regenerator-runtime/runtime\");");