Make module types explicit and convert some to ESM (#15964)

build-scripts/env.cjs

@@ -0,0 +1,35 @@
+const fs = require("fs");
+const path = require("path");
+const paths = require("./paths.cjs");
+
+module.exports = {
+  useRollup() {
+    return process.env.ROLLUP === "1";
+  },
+  useWDS() {
+    return process.env.WDS === "1";
+  },
+  isProdBuild() {
+    return (
+      process.env.NODE_ENV === "production" || module.exports.isStatsBuild()
+    );
+  },
+  isStatsBuild() {
+    return process.env.STATS === "1";
+  },
+  isTestBuild() {
+    return process.env.IS_TEST === "true";
+  },
+  isNetlify() {
+    return process.env.NETLIFY === "true";
+  },
+  version() {
+    const version = fs
+      .readFileSync(path.resolve(paths.polymer_dir, "pyproject.toml"), "utf8")
+      .match(/version\W+=\W"(\d{8}\.\d(?:\.dev)?)"/);
+    if (!version) {
+      throw Error("Version not found");
+    }
+    return version[1];
+  },
+};