Throw error for TypeScript declare const enum

packages/babel-plugin-transform-typescript/src/enum.js

@@ -3,15 +3,15 @@ import { template } from "@babel/core";
 
 export default function transpileEnum(path, t) {
   const { node } = path;
+  if (node.const) {
+    throw path.buildCodeFrameError("'const' enums are not supported.");
+  }
+
   if (node.declare) {
     path.remove();
     return;
   }
 
-  if (node.const) {
-    throw path.buildCodeFrameError("'const' enums are not supported.");
-  }
-
   const name = node.id.name;
   const fill = enumFill(path, t, node.id);
 

packages/babel-plugin-transform-typescript/test/fixtures/declarations/const-enum/input.ts

@@ -0,0 +1 @@
+declare const enum E {}

packages/babel-plugin-transform-typescript/test/fixtures/declarations/const-enum/options.json

@@ -0,0 +1 @@
+{ "throws": "'const' enums are not supported." }