fix: clone comments in cloneNode

babel · Apr 18, 2021 · f26659f · f26659f
1 parent 2918703
commit f26659f
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Showing 3 changed files with 18 additions and 16 deletions.
diff --git a/packages/babel-template/test/index.js b/packages/babel-template/test/index.js
@@ -40,6 +40,12 @@ describe("@babel/template", function () {
     expect(generator(output2).code).toBe(comments);
   });
 
+  it("should clone comments", () => {
+    const build = template(comments, { preserveComments: true });
+    const output = t.program([build(), build()]);
+    expect(generator(output).code).toBe(`${comments}\n\n${comments}`);
+  });
+
   describe("string-based", () => {
     it("should handle replacing values from an object", () => {
       const value = t.stringLiteral("some string value");

diff --git a/packages/babel-types/src/clone/cloneNode.ts b/packages/babel-types/src/clone/cloneNode.ts
@@ -102,25 +102,18 @@ export default function cloneNode<T extends t.Node>(
   return newNode;
 }
 
-function cloneCommentsWithoutLoc<T extends t.Comment>(
-  comments: ReadonlyArray<T>,
-): T[] {
-  return comments.map(
-    ({ type, value }) =>
-      ({
-        type,
-        value,
-        loc: null,
-      } as T),
-  );
-}
-
 function maybeCloneComments<T extends t.Comment>(
   comments: ReadonlyArray<T> | null,
   deep: boolean,
   withoutLoc: boolean,
 ): ReadonlyArray<T> | null {
-  return deep && withoutLoc && comments
-    ? cloneCommentsWithoutLoc(comments)
-    : comments;
+  if (!comments || !deep) {
+    return comments;
+  }
+  return comments.map(({ type, value, loc }) => {
+    if (withoutLoc) {
+      return { type, value, loc: null } as T;
+    }
+    return { type, value, loc } as T;
+  });
 }
diff --git a/packages/babel-types/test/cloning.js b/packages/babel-types/test/cloning.js
@@ -120,6 +120,9 @@ describe("cloneNode", function () {
     node.declarations[0].id.loc = {};
 
     const cloned = t.cloneNode(node, /* deep */ true, /* withoutLoc */ false);
+    expect(cloned.declarations[0].id.leadingComments[0]).not.toBe(
+      node.declarations[0].id.leadingComments[0],
+    );
     expect(cloned.declarations[0].id.leadingComments[0].loc).toBe(
       node.declarations[0].id.leadingComments[0].loc,
     );