reorganize directory and file structure

lib/util/random.js

@@ -0,0 +1,16 @@
+// IMPURE
+export const genUUID = (len=16) => {
+  const arr = crypto.getRandomValues(new Uint8Array(len));
+  let result = "";
+  for (let i=0; i<len; i++) {
+    const unsignedByte = arr[i];
+    if (unsignedByte < 16) {
+      result += '0' + unsignedByte.toString(16);
+    } else {
+      result += unsignedByte.toString(16);
+    }
+  }
+  return result;
+};
+
+console.log(genUUID())