typst-batch

A Typst → HTML batch compilation library with shared global resources.

This library was extracted from tola-ssg, a Typst-based static site generator. It is specifically designed for Typst → HTML workflows and may not be generic enough for all use cases — but feel free to give it a try!

Of course, it also works well for single document compilation when you need features like virtual file injection or friendly helper functions.

If you need:

• PDF output → Use typst directly
• Single file compilation → The official typst-cli is simpler (unless you need VFS features)

Features

• Shared fonts: Loaded once (~100ms saved per compilation)
• Cached packages: Downloaded once from Typst registry
• Incremental builds: Fingerprint-based file cache invalidation
• Structured diagnostics: Rich error messages with source locations
• Virtual file system: Inject dynamic content without physical files
• Metadata extraction: Query labeled values from compiled documents

Installation

[dependencies]
typst-batch = "0.1"

# Enable SVG rendering support (for frame-level SVG output)
# typst-batch = { version = "0.1", features = ["svg"] }

Features

Feature	Default	Description
colored-diagnostics	✓	Enable ANSI colored output via colored crate
svg		Enable SVG rendering via typst-svg (re-exports typst_svg)

Quick Start

use typst_batch::prelude::*;
use std::path::Path;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Initialize fonts once at startup (searches system fonts)
    get_fonts(&[]);

    let path = Path::new("doc.typ");
    let root = Path::new(".");

    // Compile a Typst file to HTML
    let result = compile_html(path, root)?;

    // Check for errors using trait method
    if result.diagnostics.has_errors() {
        let world = SystemWorld::new(path, root);
        eprintln!("Compilation failed:");
        eprintln!("{}", result.diagnostics.format(&world));
        return Err("compilation error".into());
    }

    // Write output
    std::fs::write("output.html", &result.html)?;
    println!("Compiled successfully! ({} bytes)", result.html.len());

    // Print summary if there are warnings
    let summary = result.diagnostics.summary();
    if !summary.is_empty() {
        eprintln!("{}", summary);  // e.g., "2 warnings"
    }

    Ok(())
}

API Overview

Compilation

Function	Description
compile_html	Compile to HTML bytes
compile_html_with_metadata	Compile with metadata extraction
compile_document	Get HtmlDocument for further processing

Metadata Extraction

Extract structured data from your Typst documents using labels:

In your .typ file:

#metadata((
  title: "My Blog Post",
  date: "2024-01-01",
  tags: ("rust", "typst"),
)) <post-meta>

= My Blog Post

This is the content...

In Rust:

use typst_batch::compile_html_with_metadata;
use std::path::Path;

let result = compile_html_with_metadata(
    Path::new("post.typ"),
    Path::new("."),
    "post-meta",  // label name without angle brackets
)?;

// Access metadata as serde_json::Value
if let Some(meta) = &result.metadata {
    println!("Title: {}", meta["title"]);
    println!("Date: {}", meta["date"]);

    // Access arrays
    if let Some(tags) = meta["tags"].as_array() {
        println!("Tags: {:?}", tags);
    }
}

Query multiple labels at once:

use typst_batch::{compile_document, query_metadata_map};

let doc_result = compile_document(path, root)?;
let metadata_map = query_metadata_map(&doc_result.document, &["post-meta", "site-config"]);

if let Some(post) = metadata_map.get("post-meta") {
    println!("Post title: {}", post["title"]);
}
if let Some(config) = metadata_map.get("site-config") {
    println!("Site name: {}", config["name"]);
}

Document Inputs (sys.inputs)

Pass runtime data to Typst documents via sys.inputs:

In Rust:

use typst_batch::compile_html_with_inputs;
use std::path::Path;

// Simple key-value pairs
let result = compile_html_with_inputs(
    Path::new("doc.typ"),
    Path::new("."),
    [("title", "Hello World"), ("author", "Alice")],
)?;

In your .typ file:

#let title = sys.inputs.at("title", default: "Untitled")
#let author = sys.inputs.at("author", default: "Unknown")

= #title
by _#author_

Performance Considerations

Using sys.inputs creates a new library instance per compilation, which has a small performance overhead. For batch compilation of many documents:

Recommended for static/global data: Use VFS (Virtual File System) to inject shared data as files. This allows all compilations to share the global library:

use typst_batch::{MapVirtualFS, set_virtual_fs, compile_html};

let mut vfs = MapVirtualFS::new();
vfs.insert("/_data/site.json", r#"{"name":"My Blog"}"#);
set_virtual_fs(vfs);

// All compilations share the global library - best performance
let result = compile_html(path, root)?;

Use sys.inputs for: Build-time variables, CLI arguments, or truly document-specific data that can't be pre-computed as VFS files.

Low-level API with SystemWorld:

use typst_batch::{SystemWorld, create_library_with_inputs};
use typst_batch::typst::foundations::{Dict, IntoValue};

// Builder pattern
let world = SystemWorld::new(path, root)
    .with_inputs([("key", "value")]);

// Or with pre-built Dict
let mut inputs = Dict::new();
inputs.insert("key".into(), "value".into_value());
let world = SystemWorld::new(path, root)
    .with_inputs_dict(inputs);

// Then compile with typst::compile(&world)

Performance Note: Using sys.inputs creates a new library instance per compilation, bypassing the shared global library. For batch compilation without inputs, use the standard compile_html() which shares resources.

Virtual File System

The VFS allows you to inject dynamic content that doesn't exist on disk, enabling flexibility and extensibility that would be difficult to achieve in Typst alone.

Use cases:

• Inject computed data (post lists, site config, build timestamps)
• Provide per-document context without modifying source files
• Implement template inheritance patterns
• Share data between documents without file I/O

Compatibility Note: VFS is a non-standard extension. Documents using virtual files won't compile with standard typst-cli. Consider this trade-off for your use case.

Virtual files are accessible in Typst via #json(), #read(), #yaml(), etc.

Simple usage with MapVirtualFS:

use typst_batch::{MapVirtualFS, set_virtual_fs};

let mut vfs = MapVirtualFS::new();

// Inject JSON data
vfs.insert("/_data/site.json", r#"{"title":"My Blog", "url":"https://example.com"}"#);

// Inject computed data
let posts_json = serde_json::to_string(&posts)?;
vfs.insert("/_data/posts.json", &posts_json);

// Register globally (call once at startup)
set_virtual_fs(vfs);

In your .typ file:

#let site = json("/_data/site.json")
#let posts = json("/_data/posts.json")

= #site.title

#for post in posts [
  - #link(post.url)[#post.title]
]

Custom VFS implementation:

use typst_batch::{VirtualFileSystem, set_virtual_fs};
use std::path::Path;

struct BuildInfoVFS {
    build_time: String,
    version: String,
}

impl VirtualFileSystem for BuildInfoVFS {
    fn read(&self, path: &Path) -> Option<Vec<u8>> {
        match path.to_str()? {
            "/_meta/build.json" => {
                let json = serde_json::json!({
                    "time": self.build_time,
                    "version": self.version,
                });
                Some(json.to_string().into_bytes())
            }
            _ => None, // Fall back to real filesystem
        }
    }
}

set_virtual_fs(BuildInfoVFS {
    build_time: chrono::Utc::now().to_rfc3339(),
    version: env!("CARGO_PKG_VERSION").into(),
});

Chained VFS - combine multiple providers:

use typst_batch::{VirtualFileSystem, set_virtual_fs};
use std::path::Path;

/// A VFS that chains multiple providers, trying each in order.
struct ChainedVFS {
    providers: Vec<Box<dyn VirtualFileSystem>>,
}

impl ChainedVFS {
    fn new() -> Self {
        Self { providers: Vec::new() }
    }

    fn add<V: VirtualFileSystem + 'static>(mut self, vfs: V) -> Self {
        self.providers.push(Box::new(vfs));
        self
    }
}

impl VirtualFileSystem for ChainedVFS {
    fn read(&self, path: &Path) -> Option<Vec<u8>> {
        // Try each provider in order, return first match
        self.providers.iter().find_map(|p| p.read(path))
    }
}

// Usage: combine site config + per-document data
let vfs = ChainedVFS::new()
    .add(site_config_vfs)
    .add(post_metadata_vfs)
    .add(build_info_vfs);

set_virtual_fs(vfs);

Diagnostics

Format compilation errors and warnings with source context:

use typst_batch::{
    compile_html, DiagnosticOptions, DisplayStyle,
    DiagnosticsExt, SystemWorld,
};
use std::path::Path;

let path = Path::new("doc.typ");
let root = Path::new(".");
let world = SystemWorld::new(path, root);
let result = compile_html(path, root)?;

// Use trait methods on diagnostics
if result.diagnostics.has_errors() {
    eprintln!("Found {} errors", result.diagnostics.error_count());
}

// Get summary
let summary = result.diagnostics.summary();
println!("{}", summary);  // "2 errors, 1 warning"

// Or get raw counts
let (errors, warnings) = result.diagnostics.counts();

// Format diagnostics (default: colored with rich snippets)
let formatted = result.diagnostics.format(&world);
eprintln!("{}", formatted);

// Format with custom options
let options = DiagnosticOptions {
    colored: true,                  // ANSI colors (requires `colored-diagnostics` feature)
    style: DisplayStyle::Rich,      // Full source snippets
    hints: true,                    // Include hints
    ..Default::default()
};
let formatted = result.diagnostics.format_with(&world, &options);

// Short style for CI/IDE (file:line:col: message)
let short = result.diagnostics.format_with(&world, &DiagnosticOptions::short());

// Filter out unwanted diagnostics
use typst_batch::DiagnosticFilter;

// Filter out HTML export warnings (shorthand)
let filtered = result.diagnostics.filter_html_warnings();

// Or use the general filter API for more control
let filtered = result.diagnostics.filter_out(&[
    DiagnosticFilter::HtmlExport,       // "html export is under active development"
    DiagnosticFilter::ExternalPackages, // Warnings from extermal packages like `@preview/...`, `@local/...`
]);

// Available filters:
// - DiagnosticFilter::HtmlExport         - HTML export development warning
// - DiagnosticFilter::ExternalPackages   - Warnings from external packages (@preview/...)
// - DiagnosticFilter::AllWarnings        - All warnings (keep only errors)
// - DiagnosticFilter::MessageContains(s) - Custom filter by message text

Full Customization with Structured Data:

For complete control over rendering (JSON, HTML, IDE integration, etc.), use .resolve() to get structured DiagnosticInfo:

use typst_batch::{DiagnosticsExt, DiagnosticInfo};

// Resolve all diagnostics to structured data
for info in result.diagnostics.resolve(&world) {
    // Full access to all diagnostic data:
    // - info.severity: Error or Warning
    // - info.message: Error message
    // - info.path: Source file path (if available)
    // - info.line, info.column: Location (1-indexed, if available)
    // - info.source_lines: Vec<SourceLine> with line_num, text, highlight range
    // - info.hints: List of hint strings
    // - info.traces: Vec<TraceInfo>, each with:
    //     - message: Trace point description
    //     - path, line, column: Location (if available)
    //     - source_lines: Source context at this trace point

    // Example: Custom JSON output
    println!("{}", serde_json::to_string_pretty(&info)?);

    // Example: Custom HTML output
    println!(r#"<div class="{:?}">"#, info.severity);
    println!("  <strong>{}:{}</strong> {}",
        info.path.as_deref().unwrap_or(""),
        info.line.unwrap_or(0),
        info.message);
    for line in &info.source_lines {
        println!("  <code>{}</code>", line.text);
    }
    println!("</div>");
}

The DiagnosticInfo struct contains:

• severity: Severity::Error or Severity::Warning
• message: The diagnostic message
• path: Source file path (optional)
• line, column: Location info (optional)
• source_lines: Vec of SourceLine with line number, text, and highlight range
• hints: Vec of hint strings
• traces: Vec of TraceInfo with call stack details

Font Configuration

use typst_batch::{FontOptions, init_fonts_with_options, get_fonts, font_count};
use std::path::Path;

// Option 1: Simple initialization with system fonts
get_fonts(&[]);

// Option 2: With custom font directories
get_fonts(&[Path::new("assets/fonts"), Path::new("content/fonts")]);

// Option 3: Detailed configuration
let options = FontOptions::new()
    .with_system_fonts(true)           // Include system fonts
    .with_custom_paths(&[              // Add custom directories
        Path::new("assets/fonts"),
    ]);

init_fonts_with_options(&options);

// Check loaded fonts
if let Some(count) = font_count() {
    println!("Loaded {} fonts", count);
}

Typst Access

For advanced use cases, access the full typst ecosystem:

// Access any typst type via the re-exported crate
use typst_batch::typst::syntax::{FileId, VirtualPath, Source};
use typst_batch::typst::diag::{SourceDiagnostic, Severity};
use typst_batch::typst::foundations::{Dict, IntoValue};
use typst_batch::typst::text::{FontBook, FontInfo, Font};

// Or use the full crates
use typst_batch::typst_html;
use typst_batch::typst_kit;

Requirements

• Typst 0.14.1

License

MIT