fix: for ESTree, attach comments when a directive is followed by a co…

…mment, then EOF If a source file contains 1) a directive, followed by 2) a comment, and nothing else, then `@babel/parser` attaches the comment to the `Directive` node as a trailing comment. The ESTree plugin handles `Directive` nodes by creating an `ExpressionStatement` node, then transferring information from the `Directive` node to the `ExpressionStatement` node. Previously, at the time it transfers information, comments hadn't yet been attached to the `Directive` node. And even if they had been, the ESTree plugin didn't do anything with comments attached to the `Directive` node. As a result, the source file's comment wasn't attached to any node in the resulting AST. With this change, the ESTree plugin generates an AST in which the comment is attached to the `ExpressionStatement` node as a trailing comment.
babel · Sep 12, 2022 · 14b764d · 14b764d
1 parent 4b7047d
commit 14b764d
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diff --git a/packages/babel-parser/src/plugins/estree.ts b/packages/babel-parser/src/plugins/estree.ts
@@ -111,6 +111,9 @@ export default (superClass: typeof Parser) =>
       // @ts-expect-error TS2339: Property 'raw' does not exist on type 'Undone '.
       expression.raw = directiveLiteral.extra.raw;
 
+      stmt.leadingComments = directive.leadingComments?.slice();
+      stmt.trailingComments = directive.trailingComments?.slice();
+
       stmt.expression = this.finishNodeAt(
         expression,
         "Literal",
@@ -175,6 +178,9 @@ export default (superClass: typeof Parser) =>
         end,
         afterBlockParse,
       );
+      if (node.directives.length) {
+        this.processComment(node);
+      }
 
       const directiveStatements = node.directives.map(d =>
         this.directiveToStmt(d),

diff --git a/packages/babel-parser/test/fixtures/estree/directives/trailing-comment-eof/input.js b/packages/babel-parser/test/fixtures/estree/directives/trailing-comment-eof/input.js
@@ -0,0 +1,3 @@
+"use strict";
+
+/** @external foo */
diff --git a/packages/babel-parser/test/fixtures/estree/directives/trailing-comment-eof/output.json b/packages/babel-parser/test/fixtures/estree/directives/trailing-comment-eof/output.json
@@ -0,0 +1,37 @@
+{
+  "type": "File",
+  "start":0,"end":35,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":20}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":35,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":20}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+        "trailingComments": [
+          {
+            "type": "CommentBlock",
+            "value": "* @external foo ",
+            "start":15,"end":35,"loc":{"start":{"line":3,"column":0,"index":15},"end":{"line":3,"column":20,"index":35}}
+          }
+        ],
+        "expression": {
+          "type": "Literal",
+          "start":0,"end":12,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":12}},
+          "value": "use strict",
+          "raw": "\"use strict\""
+        },
+        "directive": "use strict"
+      }
+    ]
+  },
+  "comments": [
+    {
+      "type": "CommentBlock",
+      "value": "* @external foo ",
+      "start":15,"end":35,"loc":{"start":{"line":3,"column":0,"index":15},"end":{"line":3,"column":20,"index":35}}
+    }
+  ]
+}