fix(babel): let babel load the presets

v7.0.0-beta.41 added `assertVersion` and a wrapper around each plugin that checks the babel API version. Since we were manually loading the presets here we weren't supplying the babel API. Using just the preset names means that babel will load them for us and everything should work as expected.

babel/babel@a479540#diff-b4beead8ad9195361b4537601cc22532

Author: eventualbuddha

package.json

@@ -68,12 +68,12 @@
     "yarnhook": "^0.1.1"
   },
   "dependencies": {
-    "@babel/core": "^7.0.0-beta.40",
-    "@babel/generator": "^7.0.0-beta.40",
-    "@babel/preset-env": "^7.0.0-beta.40",
-    "@babel/preset-typescript": "^7.0.0-beta.40",
-    "@babel/traverse": "^7.0.0-beta.40",
-    "@babel/types": "^7.0.0-beta.40",
+    "@babel/core": "^7.0.0-beta.42",
+    "@babel/generator": "^7.0.0-beta.42",
+    "@babel/preset-env": "^7.0.0-beta.42",
+    "@babel/preset-typescript": "^7.0.0-beta.42",
+    "@babel/traverse": "^7.0.0-beta.42",
+    "@babel/types": "^7.0.0-beta.42",
     "get-stream": "^3.0.0",
     "glob": "^7.1.2",
     "got": "^8.1.0",

src/transpile-requires.ts

@@ -30,10 +30,10 @@ export function hook(code: string, filename: string): string {
 
   if (!useBabelrc) {
     if (ext === '.ts') {
-      options.presets.push(require('@babel/preset-typescript').default());
+      options.presets.push('@babel/preset-typescript');
     }
 
-    options.presets.push(require('@babel/preset-env').default());
+    options.presets.push('@babel/preset-env');
   }
 
   return transform(code, options).code as string;