https://github.com/js-cst-tokens/cst-tokens comment attachment example

1.fixture.js

function /*1*/ foo /*2*/ (/*3*/) /*4*/ {/*5*/} /*6*/

2.cst.json

{
  "type": "CSTFragment",
  "cstTokens": [
    { "type": "Reference",       "value": "fragment" },
    { "type": "Literal",         "value": " "        },
    { "type": "CommentStart",    "value": "/*"       },
    { "type": "Literal",         "value": "6"        },
    { "type": "CommentEnd",      "value": "*/"       }
  ],
  "fragment": {
    "type": "Program",
    "cstTokens": [
      { "type": "Reference", "value": "body" }
    ],
    "sourceType": "module",
    "body": [
      {
        "type": "FunctionDeclaration",
        "cstTokens": [
          { "type": "Keyword",         "value": "function" },
          { "type": "Literal",         "value": " "        },
          { "type": "CommentStart",    "value": "/*"       },
          { "type": "Literal",         "value": "1"        },
          { "type": "CommentEnd",      "value": "*/"       },
          { "type": "Literal",         "value": " "        },
          { "type": "Reference",       "value": "id"       },
          { "type": "Literal",         "value": " "        },
          { "type": "CommentStart",    "value": "/*"       },
          { "type": "Literal",         "value": "2"        },
          { "type": "CommentEnd",      "value": "*/"       },
          { "type": "Literal",         "value": " "        },
          { "type": "LeftPunctuator",  "value": "("        },
          { "type": "CommentStart",    "value": "/*"       },
          { "type": "Literal",         "value": "3"        },
          { "type": "CommentEnd",      "value": "*/"       },
          { "type": "RightPunctuator", "value": ")"        },
          { "type": "CommentStart",    "value": "/*"       },
          { "type": "Literal",         "value": "4"        },
          { "type": "CommentEnd",      "value": "*/"       },
          { "type": "Literal",         "value": " "        },
          { "type": "Reference",       "value": "body"     }
        ],
        "id": {
          "type": "Identifier",
          "cstTokens": [
            { "type": "SymbolDefinition", "value": "foo" }
          ],
          "name": "foo"
        },
        "params": [],
        "body": {
          "type": "BlockStatement",
          "cstTokens": [
            { "type": "LeftPunctuator",  "value": "{"  },
            { "type": "CommentStart",    "value": "/*" },
            { "type": "Literal",         "value": "5"  },
            { "type": "CommentEnd",      "value": "*/" },
            { "type": "RightPunctuator", "value": "}"  }
          ],
          "body": []
        },
        "async": false,
        "generator": false
      }
    ]
  }
}

3.log

# Don't look too closely -- this is out of date!

 -> CSTFragment
 -> Program
 -> FunctionDeclaration
    --> eatGrammar WithSeparator
        --> eatMatchGrammar Separator
          ? [ ] Whitespace
          ? [ ] LineBreak
            --> eatMatchGrammar Comment
              ? [ ] CommentStart
              ? [ ] LineCommentStart
            <--
        <--
        startNode 1 Program
        startNode 2
        [+] Keyword
    <--
    --> eatGrammar WithWhitespace_All
     -> Identifier
        --> eatGrammar WithSeparator
            --> eatMatchGrammar Separator
              ? [+] Whitespace
              ? [ ] LineBreak
                --> eatMatchGrammar Comment
                  ? [+] CommentStart
                  ? [+] Comment
                    [+] CommentEnd
                <--
              ? [+] Whitespace
              ? [ ] LineBreak
                --> eatMatchGrammar Comment
                  ? [ ] CommentStart
                  ? [ ] LineCommentStart
                <--
              ? [ ] Whitespace
            <--
            startNode 3
            [+] SymbolDefinition
        <--
        endNode 3
     <- Identifier
        --> eatGrammar WithSeparator
            --> eatMatchGrammar Separator
              ? [+] Whitespace
              ? [ ] LineBreak
                --> eatMatchGrammar Comment
                  ? [+] CommentStart
                  ? [+] Comment
                    [+] CommentEnd
                <--
              ? [+] Whitespace
              ? [ ] LineBreak
                --> eatMatchGrammar Comment
                  ? [ ] CommentStart
                  ? [ ] LineCommentStart
                <--
              ? [ ] Whitespace
            <--
            [+] LeftPunctuator
        <--
    <--
    --> eatGrammar WithWhitespace_All
        --> eatGrammar WithSeparator
            --> eatMatchGrammar Separator
              ? [ ] Whitespace
              ? [ ] LineBreak
                --> eatMatchGrammar Comment
                  ? [+] CommentStart
                  ? [+] Comment
                    [+] CommentEnd
                <--
              ? [ ] Whitespace
              ? [ ] LineBreak
                --> eatMatchGrammar Comment
                  ? [ ] CommentStart
                  ? [ ] LineCommentStart
                <--
            <--
            [+] RightPunctuator
        <--
     -> BlockStatement
        --> eatGrammar WithSeparator
            --> eatMatchGrammar Separator
              ? [+] Whitespace
              ? [ ] LineBreak
                --> eatMatchGrammar Comment
                  ? [+] CommentStart
                  ? [+] Comment
                    [+] CommentEnd
                <--
              ? [+] Whitespace
              ? [ ] LineBreak
                --> eatMatchGrammar Comment
                  ? [ ] CommentStart
                  ? [ ] LineCommentStart
                <--
              ? [ ] Whitespace
            <--
            startNode 3
            [+] LeftPunctuator
        <--
        --> eatGrammar WithSeparator
            --> eatMatchGrammar Separator
              ? [ ] Whitespace
              ? [ ] LineBreak
                --> eatMatchGrammar Comment
                  ? [+] CommentStart
                  ? [+] Comment
                    [+] CommentEnd
                <--
              ? [ ] Whitespace
              ? [ ] LineBreak
                --> eatMatchGrammar Comment
                  ? [ ] CommentStart
                  ? [ ] LineCommentStart
                <--
            <--
            [+] RightPunctuator
        <--
        endNode 3
     <- BlockStatement
    <--
    --> eatMatchGrammar WithSeparator
        --> eatMatchGrammar Separator
          ? [+] Whitespace
          ? [ ] LineBreak
            --> eatMatchGrammar Comment
              ? [+] CommentStart
              ? [+] Comment
                [+] CommentEnd
            <--
        <--
        [x] Punctuator
    <--
    endNode 2
 <- FunctionDeclaration
    endNode 1
 <- Program
    --> eatMatchGrammar Separator
      ? [+] Whitespace
      ? [ ] LineBreak
        --> eatMatchGrammar Comment
          ? [+] CommentStart
          ? [+] Comment
            [+] CommentEnd
        <--
    <--
 <- CSTFragment

4.reprinted.js

function /*1*/ foo /*2*/ (/*3*/) /*4*/ {/*5*/} /*6*/