Library Overview

OpenXmlSdkTs is a TypeScript library for reading, writing, and manipulating Office Open XML documents -- the file formats behind .docx, .xlsx, and .pptx files. It brings the programming model of the well-known .NET Open XML SDK to the TypeScript/JavaScript ecosystem.

Key Features

• Three I/O formats -- Open and save documents as binary Blobs, Flat OPC XML strings, or Base64-encoded strings. The library auto-detects the format on open.
• Pre-atomized namespace names -- All XML element and attribute names are pre-atomized as static XName properties on dedicated namespace classes (W, S, P, A, R, NoNamespace, and more). This enables O(1) identity comparisons instead of string matching.
• LINQ to XML -- Built on ltxmlts, a TypeScript port of .NET's LINQ to XML. Query and construct XML trees with XDocument, XElement, XAttribute, XName, and XNamespace.
• Typed part navigation -- Navigate document parts through strongly-typed accessors like mainDocumentPart(), workbookPart(), and presentationPart().
• Lightweight -- Only two runtime dependencies: jszip and ltxmlts.

Class Hierarchy

OpenXmlPackage (base)
├── WmlPackage (.docx)
├── SmlPackage (.xlsx)
└── PmlPackage (.pptx)

OpenXmlPart (base)
├── WmlPart (Word parts)
├── SmlPart (Excel parts)
└── PmlPart (PowerPoint parts)

OpenXmlRelationship
Copy

Packages contain parts, and parts contain XML content. You open a package, navigate to the part you need, retrieve its XML document, query or modify it, and save the package back out.

Namespace Classes

The library provides over 48 namespace classes that give you pre-atomized XName constants for every element and attribute in the Open XML specification:

Each class exposes a static namespace property (the XNamespace) and static XName properties for every element and attribute name in that namespace.

ContentType and RelationshipType

The library includes two lookup objects that enumerate every content type and relationship type defined in the Open XML specification:

• ContentType -- Maps descriptive keys to MIME content type strings (e.g., ContentType.WmlDocument resolves to application/vnd.openxmlformats-officedocument.wordprocessingml.document.main+xml).
• RelationshipType -- Maps descriptive keys to relationship type URIs (e.g., RelationshipType.OfficeDocument resolves to the appropriate URI).

These are used when querying for parts by type or when adding new parts and relationships to a package.

Use Cases

• Office Add-ins -- Manipulate the current document inside Word, Excel, or PowerPoint add-ins using Flat OPC format.
• Server-side document generation -- Create or modify Office documents in Node.js services and APIs.
• Document transformation -- Convert, merge, split, or restructure documents programmatically.
• Inspection and analysis -- Extract text, metadata, styles, or structural information from documents.

Inspiration

OpenXmlSdkTs is inspired by the Open XML SDK for .NET. Developers familiar with the .NET SDK will recognize the same package/part/relationship model and the same LINQ to XML approach to working with document content.