docx-handlebars-0.2.3 has been yanked.

docx-handlebars

A Rust library for processing DOCX files with Handlebars templates, supporting multiple platforms:

🦀 Rust native
🌐 WebAssembly (WASM)
📦 npm package
🟢 Node.js
🦕 Deno
🌍 Browser
📋 JSR (JavaScript Registry)

Features

✅ Smart Merging: Automatically handles Handlebars syntax split by XML tags
✅ DOCX Validation: Built-in file format validation to ensure valid input files
✅ Handlebars Support: Full template engine with variables, conditionals, loops, and helper functions
✅ Cross-platform: Rust native + WASM support for multiple runtimes
✅ TypeScript: Complete type definitions and intelligent code completion
✅ Zero Dependencies: WASM binary with no external dependencies
✅ Error Handling: Detailed error messages and type-safe error handling

Installation

Rust

cargo add docx-handlebars

npm

npm install docx-handlebars

Deno

import { render, init } from "jsr:@sail/docx-handlebars";

Usage Examples

Rust

use docx_handlebars::render_handlebars;
use serde_json::json;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Read DOCX template file
    let template_bytes = std::fs::read("template.docx")?;
    
    // Prepare data
    let data = json!({
        "name": "John Doe",
        "company": "ABC Technology Ltd.",
        "position": "Software Engineer",
        "projects": [
            {"name": "Project A", "status": "Completed"},
            {"name": "Project B", "status": "In Progress"}
        ],
        "has_bonus": true,
        "bonus_amount": 5000
    });
    
    // Render template
    let result = render_handlebars(template_bytes, &data)?;
    
    // Save result
    std::fs::write("output.docx", result)?;
    
    Ok(())
}

JavaScript/TypeScript (Node.js)

import { render, init } from 'docx-handlebars';
import fs from 'fs';

async function processTemplate() {
    // Initialize WASM module
    await init();
    
    // Read template file
    const templateBytes = fs.readFileSync('template.docx');
    
    // Prepare data
    const data = {
        name: "Jane Smith",
        company: "XYZ Tech Ltd.",
        position: "Senior Developer",
        projects: [
            { name: "E-commerce Platform", status: "Completed" },
            { name: "Mobile App", status: "In Development" }
        ],
        has_bonus: true,
        bonus_amount: 8000
    };
    
    // Render template
    const result = render(templateBytes, JSON.stringify(data));
    
    // Save result
    fs.writeFileSync('output.docx', new Uint8Array(result));
}

processTemplate().catch(console.error);

Deno

import { render, init } from "https://deno.land/x/docx_handlebars/mod.ts";

async function processTemplate() {
    // Initialize WASM module
    await init();
    
    // Read template file
    const templateBytes = await Deno.readFile("template.docx");
    
    // Prepare data
    const data = {
        name: "Alice Johnson",
        department: "R&D Department",
        projects: [
            { name: "AI Customer Service", status: "Live" },
            { name: "Data Visualization Platform", status: "In Development" }
        ]
    };
    
    // Render template
    const result = render(templateBytes, JSON.stringify(data));
    
    // Save result
    await Deno.writeFile("output.docx", new Uint8Array(result));
}

if (import.meta.main) {
    await processTemplate();
}

Browser

<!DOCTYPE html>
<html>
<head>
    <title>DOCX Handlebars Example</title>
</head>
<body>
    <input type="file" id="fileInput" accept=".docx">
    <button onclick="processFile()">Process Template</button>
    
    <script type="module">
        import { render, init } from './pkg/docx_handlebars.js';
        
        // Initialize WASM
        await init();
        
        window.processFile = async function() {
            const fileInput = document.getElementById('fileInput');
            const file = fileInput.files[0];
            
            if (!file) return;
            
            const arrayBuffer = await file.arrayBuffer();
            const templateBytes = new Uint8Array(arrayBuffer);
            
            const data = {
                name: "John Doe",
                company: "Example Company"
            };
            
            try {
                const result = render(templateBytes, JSON.stringify(data));
                
                // Download result
                const blob = new Blob([new Uint8Array(result)], {
                    type: 'application/vnd.openxmlformats-officedocument.wordprocessingml.document'
                });
                const url = URL.createObjectURL(blob);
                const a = document.createElement('a');
                a.href = url;
                a.download = 'processed.docx';
                a.click();
            } catch (error) {
                console.error('Processing failed:', error);
            }
        };
    </script>
</body>
</html>

Template Syntax

Basic Variable Substitution

Employee Name: {{name}}
Company: {{company}}
Position: {{position}}

Conditional Rendering

{{#if has_bonus}}
Bonus: ${{bonus_amount}}
{{else}}
No bonus
{{/if}}

{{#unless is_intern}}
Full-time employee
{{/unless}}

Loop Rendering

Project Experience:
{{#each projects}}
- {{name}}: {{description}} ({{status}})
{{/each}}

Skills:
{{#each skills}}
{{@index}}. {{this}}
{{/each}}

Helper Functions

Built-in helper functions:

{{upper name}}           <!-- Convert to uppercase -->
{{lower company}}        <!-- Convert to lowercase -->
{{len projects}}         <!-- Array length -->
{{#if (eq status "completed")}}Completed{{/if}}    <!-- Equality comparison -->
{{#if (gt score 90)}}Excellent{{/if}}              <!-- Greater than comparison -->
{{#if (lt age 30)}}Young{{/if}}                    <!-- Less than comparison -->

Complex Example

=== Employee Report ===

Basic Information:
Name: {{employee.name}}
Department: {{employee.department}}
Position: {{employee.position}}
Hire Date: {{employee.hire_date}}

{{#if employee.has_bonus}}
💰 Bonus: ${{employee.bonus_amount}}
{{/if}}

Project Experience ({{len projects}} total):
{{#each projects}}
{{@index}}. {{name}}
   Description: {{description}}
   Status: {{status}}
   Team Size: {{team_size}} people
   
{{/each}}

Skills Assessment:
{{#each skills}}
- {{name}}: {{level}}/10 ({{years}} years experience)
{{/each}}

To delete an entire table row, simply add the following to any cell in that row:
{{removeTableRow}}

{{#if (gt performance.score 90)}}
🎉 Performance Rating: Excellent
{{else if (gt performance.score 80)}}
👍 Performance Rating: Good
{{else}}
📈 Performance Rating: Needs Improvement
{{/if}}

Image:
{{img base64_image_data [width] [height]}}
  only height: {{img base64 "" 200}}
  only width: {{img base64 300}}
  no width/height: {{img base64}}
  both width/height: {{img base64 300 200}}

Error Handling

The library provides detailed error types and messages:

Rust

use docx_handlebars::{render_handlebars, DocxError};

match render_handlebars(template_bytes, &data) {
    Ok(result) => {
        println!("Processing successful!");
        std::fs::write("output.docx", result)?;
    }
    Err(e) => match e.downcast_ref::<DocxError>() {
        Some(DocxError::InvalidZipFormat) => {
            eprintln!("Error: File is not a valid ZIP/DOCX format");
        }
        _ => {
            eprintln!("Other error: {}", e);
        }
    }
}

JavaScript/TypeScript

try {
    const result = render(templateBytes, JSON.stringify(data));
    console.log('Processing successful!');
} catch (error) {
    console.error('Processing failed:', error);
}

Build and Development

Build WASM Packages

# Build all targets
npm run build

# Or build separately
npm run build:web    # Browser version
npm run build:npm    # Node.js version 
npm run build:jsr    # Deno version

Run Examples

# Rust example
cargo run --example rust_example

# Node.js example
node examples/node_example.js

# Deno example  
deno run --allow-read --allow-write examples/deno_example.ts

# Browser example
cd tests/npm_test
node serve.js
# Then open http://localhost:8080 in your browser
# Select examples/template.docx file to test

Technical Features

Smart Merging Algorithm

The core innovation of this library is the intelligent merging of Handlebars syntax that has been split by XML tags. In DOCX files, when users input template syntax, Word may split it into multiple XML tags.

File Validation

Built-in DOCX file validation ensures input file integrity:

ZIP Format Validation: Check file signature and structure
DOCX Structure Validation: Ensure required files are present
- [Content_Types].xml
- _rels/.rels
- word/document.xml
MIME Type Validation: Verify correct content types

Performance and Compatibility

Zero Copy: Efficient memory management between Rust and WASM
Streaming Processing: Suitable for handling large DOCX files
Cross-platform: Support for Windows, macOS, Linux, Web
Modern Browsers: Support for all modern browsers that support WASM

License

This project is licensed under the MIT License - see the LICENSE-MIT file for details.

docx-handlebars 0.2.3

docx-handlebars

Features

Installation

Rust

npm

Deno

Usage Examples

Rust

JavaScript/TypeScript (Node.js)

Deno

Browser

Template Syntax

Basic Variable Substitution

Conditional Rendering

Loop Rendering

Helper Functions

Complex Example

Error Handling

Rust

JavaScript/TypeScript

Build and Development

Build WASM Packages

Run Examples

Technical Features

Smart Merging Algorithm

File Validation

Performance and Compatibility

License

Support