Method finalizeComment

packages/babel-parser/src/parser/comments.ts:155–223

* Assign the comments of comment whitespaces to related AST nodes. * Also adjust innerComments following trailing comma.

(commentWS: CommentWhitespace)

   * Also adjust innerComments following trailing comma.
   */
  finalizeComment(commentWS: CommentWhitespace) {
    const { comments } = commentWS;
    if (commentWS.leadingNode !== null || commentWS.trailingNode !== null) {
      if (commentWS.leadingNode !== null) {
        setTrailingComments(commentWS.leadingNode, comments);
      }
      if (commentWS.trailingNode !== null) {
        setLeadingComments(commentWS.trailingNode, comments);
      }
    } else {
      /*:: invariant(commentWS.containingNode !== null) */
      const node = commentWS.containingNode!;
      const commentStart = commentWS.start;
      if (
        this.input.charCodeAt(this.offsetToSourcePos(commentStart) - 1) ===
        charCodes.comma
      ) {
        // If a commentWhitespace follows a comma and the containingNode allows
        // list structures with trailing comma, merge it to the trailingComment
        // of the last non-null list element
        switch (node.type) {
          case "ObjectExpression":
          case "ObjectPattern":
            adjustInnerComments(node, node.properties, commentWS);
            break;
          case "CallExpression":
          case "NewExpression":
          case "OptionalCallExpression":
            adjustInnerComments(node, node.arguments, commentWS);
            break;
          case "ImportExpression":
            adjustInnerComments(
              node,
              [node.source, node.options ?? null],
              commentWS,
            );
            break;
          case "FunctionDeclaration":
          case "FunctionExpression":
          case "ArrowFunctionExpression":
          case "ObjectMethod":
          case "ClassMethod":
          case "ClassPrivateMethod":
          case "TSTypeParameterDeclaration":
            adjustInnerComments(node, node.params, commentWS);
            break;
          case "ArrayExpression":
          case "ArrayPattern":
            adjustInnerComments(node, node.elements, commentWS);
            break;
          case "ExportNamedDeclaration":
          case "ImportDeclaration":
            adjustInnerComments(node, node.specifiers, commentWS);
            break;
          case "TSEnumBody":
            adjustInnerComments(node, node.members, commentWS);
            break;
          case "TSInterfaceBody":