docx to mammoth roundtrip: working versions (tested 2026-10-15)

{
  "name": "docx-mammoth-roundtrip",
  "private": true,
  "type": "module",
  "scripts": {
    "test": "node --import tsx --test test/*.test.ts"
  },
  "dependencies": {
    "docx": "9.11.0",
    "mammoth": "1.13.0"
  },
  "devDependencies": {
    "@types/node": "26.6.5",
    "tsx": "4.23.15"
  }
}

import {
  Document,
  HeadingLevel,
  Packer,
  Paragraph,
  Table,
  TableCell,
  TableRow,
} from "docx";

export async function generateDocx(): Promise<Buffer> {
  const doc = new Document({
    sections: [
      {
        children: [
          new Paragraph({
            text: "Quarterly Report",
            heading: HeadingLevel.HEADING_1,
          }),
          new Paragraph({
            text: "This document is generated entirely in memory for roundtrip testing.",
          }),
          new Table({
            rows: [
              new TableRow({
                children: [
                  new TableCell({ children: [new Paragraph("Item")] }),
                  new TableCell({ children: [new Paragraph("Qty")] }),
                ],
              }),
              new TableRow({
                children: [
                  new TableCell({ children: [new Paragraph("Widgets")] }),
                  new TableCell({ children: [new Paragraph("3")] }),
                ],
              }),
              new TableRow({
                children: [
                  new TableCell({ children: [new Paragraph("Gadgets")] }),
                  new TableCell({ children: [new Paragraph("5")] }),
                ],
              }),
            ],
          }),
        ],
      },
    ],
  });

  return Packer.toBuffer(doc);
}

import mammoth from "mammoth";

export async function toHtml(buffer: Buffer): Promise<string> {
  const result = await mammoth.convertToHtml({ buffer });
  return result.value;
}

export async function toRawText(buffer: Buffer): Promise<string> {
  const result = await mammoth.extractRawText({ buffer });
  return result.value;
}

import { test } from "node:test";
import assert from "node:assert/strict";
import { generateDocx } from "../src/generate.ts";
import { toHtml, toRawText } from "../src/read.ts";

test("generates a non-empty in-memory docx buffer", async () => {
  const buffer = await generateDocx();
  assert.ok(Buffer.isBuffer(buffer));
  assert.ok(buffer.length > 0);
  assert.equal(buffer.subarray(0, 2).toString("binary"), "PK");
});

test("convertToHtml renders the heading, paragraph and table", async () => {
  const buffer = await generateDocx();
  const html = await toHtml(buffer);
  assert.match(html, /<h1>Quarterly Report<\/h1>/);
  assert.match(html, /generated entirely in memory/);
  assert.match(html, /<table>/);
  assert.match(html, /<td><p>Widgets<\/p><\/td>/);
  assert.match(html, /<td><p>3<\/p><\/td>/);
});

test("extractRawText preserves the document text", async () => {
  const buffer = await generateDocx();
  const text = await toRawText(buffer);
  assert.match(text, /Quarterly Report/);
  assert.match(text, /generated entirely in memory/);
  assert.match(text, /Widgets/);
  assert.match(text, /Gadgets/);
  assert.match(text, /\b3\b/);
  assert.match(text, /\b5\b/);
});