Parse w/ recast directly in the transform

This is necessary to conditionally include the 'jsx' babylon plugin
when transforming a .tsx file. See also:
facebook/jscodeshift#180 (comment)

transforms/__tests__/reverse-identifiers.js

@@ -2,10 +2,16 @@
 
 const transform = require('../reverse-identifiers');
 const defineInlineTest = require('jscodeshift/dist/testUtils').defineInlineTest;
+const runInlineTest = require('jscodeshift/dist/testUtils').runInlineTest;
 
-defineInlineTest(
-  transform,
-  {},
-  'let foo: string = ""',
-  'let oof: string = ""'
-);
+it('transforms correctly', () => {
+  runInlineTest(
+    transform,
+    {},
+    {
+      path: 'source.ts',
+      source: 'let foo: string = <string>"somestring"',
+    },
+    'let oof: string = <string>"somestring"',
+  );
+});

transforms/reverse-identifiers.js

@@ -8,34 +8,30 @@
  */
 
 const babylon = require('babylon');
+const recast = require('recast');
 
 /**
  * Example jscodeshift transformer. Simply reverses the names of all
  * identifiers. Stolen from:
  * https://github.com/facebook/jscodeshift/blob/7be2557f369794e915afe7f91ab81b1215e66857/sample/reverse-identifiers.js
  */
 function transform(file, api) {
+  const parse = source => babylon.parse(source, {
+    sourceType: 'module',
+    plugins: file.path.endsWith('.tsx') ? ['jsx', 'typescript'] : ['typescript'],
+  });
+
   const j = api.jscodeshift;
-
-  return j(file.source)
+  
+  return j(recast.parse(file.source, { parser: { parse } }))
     .find(j.Identifier)
     .replaceWith(
-      p => {
-        return {
-          ...j.identifier(p.node.name.split('').reverse().join('')),
-          typeAnnotation: p.value.typeAnnotation
-        };
-      }
+      p => ({
+        ...p.node,
+        name: p.node.name.split('').reverse().join('')
+      })
     )
     .toSource();
 }
 
 module.exports = transform;
-module.exports.parser = {
-  parse: source => babylon.parse(source, {
-    sourceType: 'module',
-    plugins: [
-      'typescript'
-    ],
-  }),
-};