DOCX creation, editing, and analysis

Overview

A .docx file is a ZIP archive containing XML files.

Quick Reference

pandoc

docx-js

Reading Content

# Text extraction with tracked changes
pandoc --track-changes=all document.docx -o output.md

# Raw XML access
python3 scripts/unpack.py document.docx unpacked/

Converting to Images

soffice --headless --convert-to pdf document.docx
pdftoppm -jpeg -r 150 document.pdf page

Creating New Documents

Generate .docx files with JavaScript. Install:

npm install -g docx

Setup

const { Document, Packer, Paragraph, TextRun, Table, TableRow, TableCell, ImageRun,
        Header, Footer, AlignmentType, PageOrientation, LevelFormat, ExternalHyperlink,
        TableOfContents, HeadingLevel, BorderStyle, WidthType, ShadingType,
        VerticalAlign, PageNumber, PageBreak } = require('docx');

const doc = new Document({ sections: [{ children: [/* content */] }] });
Packer.toBuffer(doc).then(buffer => fs.writeFileSync("doc.docx", buffer));

Page Size

// CRITICAL: docx-js defaults to A4, not US Letter
// Always set page size explicitly for consistent results
sections: [{
  properties: {
    page: {
      size: {
        width: 12240,   // 8.5 inches in DXA
        height: 15840   // 11 inches in DXA
      },
      margin: { top: 1440, right: 1440, bottom: 1440, left: 1440 } // 1 inch margins
    }
  },
  children: [/* content */]
}]

Common page sizes (DXA units, 1440 DXA = 1 inch):

Styles (Override Built-in Headings)

Use Arial as the default font (universally supported). Keep titles black for readability.

const doc = new Document({
  styles: {
    default: { document: { run: { font: "Arial", size: 24 } } }, // 12pt default
    paragraphStyles: [
      // IMPORTANT: Use exact IDs to override built-in styles
      { id: "Heading1", name: "Heading 1", basedOn: "Normal", next: "Normal", quickFormat: true,
        run: { size: 32, bold: true, font: "Arial" },
        paragraph: { spacing: { before: 240, after: 240 }, outlineLevel: 0 } }, // outlineLevel required for TOC
      { id: "Heading2", name: "Heading 2", basedOn: "Normal", next: "Normal", quickFormat: true,
        run: { size: 28, bold: true, font: "Arial" },
        paragraph: { spacing: { before: 180, after: 180 }, outlineLevel: 1 } },
    ]
  },
  sections: [{
    children: [
      new Paragraph({ heading: HeadingLevel.HEADING_1, children: [new TextRun("Title")] }),
    ]
  }]
});

Lists (NEVER use unicode bullets)

// ❌ WRONG - never manually insert bullet characters
new Paragraph({ children: [new TextRun("• Item")] })  // BAD
new Paragraph({ children: [new TextRun("\u2022 Item")] })  // BAD

// ✅ CORRECT - use numbering config with LevelFormat.BULLET
const doc = new Document({
  numbering: {
    config: [
      { reference: "bullets",
        levels: [{ level: 0, format: LevelFormat.BULLET, text: "•", alignment: AlignmentType.LEFT,
          style: { paragraph: { indent: { left: 720, hanging: 360 } } } }] },
      { reference: "numbers",
        levels: [{ level: 0, format: LevelFormat.DECIMAL, text: "%1.", alignment: AlignmentType.LEFT,
          style: { paragraph: { indent: { left: 720, hanging: 360 } } } }] },
    ]
  },
  sections: [{
    children: [
      new Paragraph({ numbering: { reference: "bullets", level: 0 },
        children: [new TextRun("Bullet item")] }),
      new Paragraph({ numbering: { reference: "numbers", level: 0 },
        children: [new TextRun("Numbered item")] }),
    ]
  }]
});

// ⚠️ Each reference creates INDEPENDENT numbering
// Same reference = continues (1,2,3 then 4,5,6)
// Different reference = restarts (1,2,3 then 1,2,3)

Tables

CRITICAL: Tables need dual widths - set both

columnWidths

width

// CRITICAL: Always set table width for consistent rendering
// CRITICAL: Use ShadingType.CLEAR (not SOLID) to prevent black backgrounds
const border = { style: BorderStyle.SINGLE, size: 1, color: "CCCCCC" };
const borders = { top: border, bottom: border, left: border, right: border };

new Table({
  width: { size: 100, type: WidthType.PERCENTAGE }, // Always set table width
  columnWidths: [4680, 4680], // Set at table level (DXA: 1440 = 1 inch)
  rows: [
    new TableRow({
      children: [
        new TableCell({
          borders,
          width: { size: 4680, type: WidthType.DXA }, // Also set on each cell
          shading: { fill: "D5E8F0", type: ShadingType.CLEAR }, // CLEAR not SOLID
          margins: { top: 80, bottom: 80, left: 120, right: 120 }, // Cell padding (internal, not added to width)
          children: [new Paragraph({ children: [new TextRun("Cell")] })]
        })
      ]
    })
  ]
})

Table width calculation:

Use

WidthType.PERCENTAGE

WidthType.DXA

// Option 1: Percentage (recommended - automatically fits content area)
width: { size: 100, type: WidthType.PERCENTAGE }

// Option 2: DXA (precise control)
// Table width = sum of columnWidths = content width
// US Letter with 1" margins: 12240 - 2880 = 9360 DXA
width: { size: 9360, type: WidthType.DXA },
columnWidths: [7000, 2360]  // Must sum to table width

Width rules:

• Table width must equal the sum of

  columnWidths

• Cell

  width

  must match corresponding

  columnWidth

• Cell

  margins

  are internal padding - they reduce content area, not add to cell width
• For full-width tables: use content width (page width minus left and right margins)

Images

// CRITICAL: type parameter is REQUIRED
new Paragraph({
  children: [new ImageRun({
    type: "png", // Required: png, jpg, jpeg, gif, bmp, svg
    data: fs.readFileSync("image.png"),
    transformation: { width: 200, height: 150 },
    altText: { title: "Title", description: "Desc", name: "Name" } // All three required
  })]
})

Page Breaks

// CRITICAL: PageBreak must be inside a Paragraph
new Paragraph({ children: [new PageBreak()] })

// Or use pageBreakBefore
new Paragraph({ pageBreakBefore: true, children: [new TextRun("New page")] })

Table of Contents

// CRITICAL: Headings must use HeadingLevel ONLY - no custom styles
new TableOfContents("Table of Contents", { hyperlink: true, headingStyleRange: "1-3" })

Headers/Footers

sections: [{
  properties: {
    page: { margin: { top: 1440, right: 1440, bottom: 1440, left: 1440 } } // 1440 = 1 inch
  },
  headers: {
    default: new Header({ children: [new Paragraph({ children: [new TextRun("Header")] })] })
  },
  footers: {
    default: new Footer({ children: [new Paragraph({
      children: [new TextRun("Page "), new TextRun({ children: [PageNumber.CURRENT] })]
    })] })
  },
  children: [/* content */]
}]

Critical Rules for docx-js

• Set page size explicitly - docx-js defaults to A4; use US Letter (12240 x 15840 DXA) for US documents
• Never use

  \n

  - use separate Paragraph elements
• Never use unicode bullets - use

  LevelFormat.BULLET

  with numbering config
• PageBreak must be in Paragraph - standalone creates invalid XML
• ImageRun requires

  type

  - always specify png/jpg/etc
• Always set table

  width

  - use

  { size: 100, type: WidthType.PERCENTAGE }

  for full width
• Tables need dual widths -

  columnWidths

  array AND cell

  width

  , both must match
• Table width = sum of columnWidths - for DXA, ensure they add up exactly
• Always add cell margins - use

  margins: { top: 80, bottom: 80, left: 120, right: 120 }

  for readable padding
• Use

  ShadingType.CLEAR

  - never SOLID for table shading
• TOC requires HeadingLevel only - no custom styles on heading paragraphs
• Override built-in styles - use exact IDs: "Heading1", "Heading2", etc.
• Include

  outlineLevel

  - required for TOC (0 for H1, 1 for H2, etc.)

Editing Existing Documents

Follow all 3 steps in order.

Step 1: Unpack

python3 scripts/unpack.py document.docx unpacked/

Extracts XML, pretty-prints, merges adjacent runs, and converts smart quotes to XML entities (

“

--merge-runs false

Step 2: Edit XML

Edit files in

unpacked/word/

Always use "Claude" as the author for tracked changes and comments.

Use the Edit tool directly for string replacement. Do not write Python scripts. Scripts introduce unnecessary complexity. The Edit tool shows exactly what is being replaced.

CRITICAL: Use smart quotes for new content. When adding text with apostrophes or quotes, use XML entities to produce smart quotes:

<!-- Use these entities for professional typography -->
<w:t>Here&#x2019;s a quote: &#x201C;Hello&#x201D;</w:t>

‘

’

“

”

Adding comments: Use

comment.py

python3 scripts/comment.py unpacked/ 0 "Comment text with & and ’"
python3 scripts/comment.py unpacked/ 1 "Reply text" --parent 0  # reply to comment 0

Then add markers to document.xml (see Comments in XML Reference).

Step 3: Pack

python3 scripts/pack.py unpacked/ output.docx --original document.docx

Validates with auto-repair, condenses XML, and creates DOCX. Use

--validate false

Auto-repair will fix:

• durableId

  >= 0x7FFFFFFF (regenerates valid ID)
• Missing

  xml:space="preserve"

  on

  <w:t>

  with whitespace

Auto-repair won't fix:

• Malformed XML, invalid element nesting, missing relationships, schema violations

Common Pitfalls

• Replace entire

  <w:r>

  elements: When adding tracked changes, replace the whole

  <w:r>...</w:r>

  block with

  <w:del>...<w:ins>...

  as siblings. Don't inject tracked change tags inside a run.
• Preserve

  <w:rPr>

  formatting: Copy the original run's

  <w:rPr>

  block into your tracked change runs to maintain bold, font size, etc.

XML Reference

Schema Compliance

• Element order in

  <w:pPr>

  :

  <w:pStyle>

  ,

  <w:numPr>

  ,

  <w:spacing>

  ,

  <w:ind>

  ,

  <w:jc>

  ,

  <w:rPr>

  last
• Whitespace: Add

  xml:space="preserve"

  to

  <w:t>

  with leading/trailing spaces
• RSIDs: Must be 8-digit hex (e.g.,

  00AB1234

  )

Tracked Changes

Insertion:

<w:ins w:id="1" w:author="Claude" w:date="2025-01-01T00:00:00Z">
  <w:r><w:t>inserted text</w:t></w:r>
</w:ins>

Deletion:

<w:del w:id="2" w:author="Claude" w:date="2025-01-01T00:00:00Z">
  <w:r><w:delText>deleted text</w:delText></w:r>
</w:del>

Minimal edits - only mark what changes:

<!-- Change "30 days" to "60 days" -->
<w:r><w:t>The term is </w:t></w:r>
<w:del w:id="1" w:author="Claude" w:date="...">
  <w:r><w:delText>30</w:delText></w:r>
</w:del>
<w:ins w:id="2" w:author="Claude" w:date="...">
  <w:r><w:t>60</w:t></w:r>
</w:ins>
<w:r><w:t> days.</w:t></w:r>

Rejecting another author's insertion - nest deletion inside their insertion:

<w:ins w:author="Jane" w:id="5">
  <w:del w:author="Claude" w:id="10">
    <w:r><w:delText>their inserted text</w:delText></w:r>
  </w:del>
</w:ins>

Restoring another author's deletion - add insertion after (don't modify their deletion):

<w:del w:author="Jane" w:id="5">
  <w:r><w:delText>deleted text</w:delText></w:r>
</w:del>
<w:ins w:author="Claude" w:id="10">
  <w:r><w:t>deleted text</w:t></w:r>
</w:ins>

Comments

After running

comment.py

--parent

<!-- Comment 0 with reply 1 nested inside -->
<w:commentRangeStart w:id="0"/>
  <w:commentRangeStart w:id="1"/>
  <w:r><w:t>text</w:t></w:r>
  <w:commentRangeEnd w:id="1"/>
<w:commentRangeEnd w:id="0"/>
<w:r><w:rPr><w:rStyle w:val="CommentReference"/></w:rPr><w:commentReference w:id="0"/></w:r>
<w:r><w:rPr><w:rStyle w:val="CommentReference"/></w:rPr><w:commentReference w:id="1"/></w:r>

Images

1. Add image file to

   word/media/

2. Add relationship to

   word/_rels/document.xml.rels

   :

<Relationship Id="rId5" Type=".../image" Target="media/image1.png"/>

3. Add content type to

   [Content_Types].xml

   :

<Default Extension="png" ContentType="image/png"/>

4. Reference in document.xml:

<w:drawing>
  <wp:inline>
    <wp:extent cx="914400" cy="914400"/>  <!-- EMUs: 914400 = 1 inch -->
    <a:graphic>
      <a:graphicData uri=".../picture">
        <pic:pic>
          <pic:blipFill><a:blip r:embed="rId5"/></pic:blipFill>
        </pic:pic>
      </a:graphicData>
    </a:graphic>
  </wp:inline>
</w:drawing>

Dependencies

• pandoc: Text extraction
• docx:

  npm install -g docx

  (new documents)
• LibreOffice: PDF conversion
• Poppler:

  pdftoppm

  for images