Numbering headings

[isNotOkay]

Hello,

I am trying to number my headings like this:

1
  1.1
  1.2
  1.3
2
  2.1
  2.2

I found this example, but it's not working:
https://codepen.io/wcqrnj/pen/QWwKVNQ?editors=1010

Does anyone have a working example?

I am using docx version 8.2.1.

Edit:

Here is a working example for those interested:

import * as fs from "fs";
import {AlignmentType, Document, HeadingLevel, LevelFormat, Packer, Paragraph} from "docx";

const doc = new Document({
    numbering: {
        config: [
            {
                reference: "headings",
                levels: [
                    {
                        level: 0,
                        format: LevelFormat.DECIMAL,
                        text: "%1",
                        alignment: AlignmentType.START,
                    },
                    {
                        level: 1,
                        format: LevelFormat.DECIMAL,
                        text: "%1.%2",
                        alignment: AlignmentType.START
                    }
                ],
            }
        ],
    },
    sections: [
        {
            children: [
                new Paragraph({
                    text: "A",
                    heading: HeadingLevel.HEADING_1,
                    numbering: {
                        reference: "headings",
                        level: 0,
                    },
                }),
                new Paragraph({
                    text: "A - 1",
                    heading: HeadingLevel.HEADING_2,
                    numbering: {
                        reference: "headings",
                        level: 1,
                    },
                }),
                new Paragraph({
                    text: "B",
                    heading: HeadingLevel.HEADING_1,
                    numbering: {
                        reference: "headings",
                        level: 0,
                    },
                }),
                new Paragraph({
                    text: "B - 1",
                    heading: HeadingLevel.HEADING_2,
                    numbering: {
                        reference: "headings",
                        level: 1,
                    },
                })
            ],
        },
    ],
});

Packer.toBuffer(doc).then((buffer) => {
    fs.writeFileSync("My Document.docx", buffer);
});