TL;DR

Rspack now builds ESM (EcmaScript Modules) significantly faster, with reported speedups of up to 68% for certain projects, thanks to optimizations in module linking and static worker URL generation.

New

• Faster ESM Builds: Building with output.module is much faster.
• Static Worker URLs: Rspack can now emit static URLs for workers, improving performance and compatibility.
• Fine-grained import.meta Control: You can now precisely configure how import.meta properties are handled during parsing.

Fixes Worth Knowing

• Fixed issues with runtime global rendering and Module Federation identifiers.
• Improved error messages to include file paths for easier debugging.
• Worker loading now respects the RSPACK_BINDING environment variable.

Before You Upgrade

If you are using workers, review your Rspack configuration to see if the new worker.url: 'new-url-relative' option improves your build.

TL;DR

Rspack significantly improves build performance with optimizations across multiple areas, including dependency handling, resource parsing, and loader processing. It also introduces experimental runtime mode options and enhanced caching capabilities.

New

• React Compiler Support: Rspack now supports the React Compiler, potentially speeding up React builds.
• Persistent Cache Control: New options (maxAge, maxGenerations) provide finer-grained control over persistent cache cleanup (caching - storage of build artifacts).
• JS API Exposure: New JavaScript APIs expose module error information and provided exports for advanced use cases.

Fixes Worth Knowing

• CSS Module Ident Preservation: Fixes an issue where CSS module identifiers were being lost.
• Chunk Size Grouping: Chunk size grouping now aligns with Webpack’s behavior.
• Module Federation Stability: Improved stability for consuming shared runtime outputs in module federation setups.

Before You Upgrade

• Review the documentation for the new experimental.runtimeMode option if you are interested in exploring new runtime behaviors.

TL;DR

Rspack now correctly exposes assets in module federation (a code sharing technique) manifests, resolving issues with dynamically loaded resources.

Fixes Worth Knowing

• Fixed timing logger inaccuracies to better align with Webpack’s build phases.
• Corrected an issue where assets weren’t being properly exposed in module federation manifests.

TL;DR

Rspack v1.7.0 introduces significant performance improvements by upgrading to SWC v50 and enables lazy compilation by default for dynamic imports, speeding up build times.

Breaking

• Experiments API Changes: The experiments.inlineConst, experiments.inlineEnum, and experiments.lazyBarrel options are now stable and have moved from the experiments object to the module.parser.javascript and optimization objects in your configuration.

New

• Asset Module Support: Added support for type: 'text' in asset modules, allowing for more flexible handling of different asset types.
• Universal Chunk Loading: Implemented UniversalCompileAsyncWasmPlugin for improved loading of asynchronous chunks.

Fixes Worth Knowing

• Fixed issues with relative resource paths on Windows in source maps.
• Resolved problems with Wasm plugin panics when using persistent caching.
• Improved handling of ignored asset modules and data URL exports.
• Corrected issues with ignoreWarnings and improved documentation.

Before You Upgrade

• Update your configuration to reflect the changes to the experimental features, moving them from experiments to module.parser.javascript and optimization.

TL;DR

Rspack now includes a new, opt-in CSS minimizer powered by Lightning CSS (a fast CSS compiler), offering improved CSS tree shaking and the potential to remove PostCSS (CSS processing tool) for downgrading.

New

• LightningCSS Minimizer: A new CSS minimizer is available for faster CSS processing and tree shaking.
• Worker Loader Compatibility: Added temporary compatibility for projects using worker-loader (for handling web workers).

Fixes Worth Knowing

• Fixed issues with CSS modules incorrectly composing class names.
• Resolved a segmentation fault with custom loaders.
• Improved handling of URL dependencies in minimized CSS.
• Corrected source map generation issues.

Before You Upgrade

If you are currently using PostCSS solely for browser downgrading, you may be able to remove it after enabling the LightningCSS minimizer.

TL;DR

Rspack v0.7.0 introduces significant performance improvements and new features like lazy compilation, while also deprecating older APIs in preparation for future development.

Breaking

• Compiler and MultiCompiler APIs are deprecated. (These are core Rspack interfaces, requiring code updates for users directly interacting with them.)
• Compilation API is deprecated. (Similar to the above, this impacts advanced users extending Rspack’s compilation process.)
• SWC has been updated. (May require adjustments if relying on specific SWC behavior.)

New

• Lazy compilation is now supported. (Improves startup time for larger projects by deferring compilation of modules.)
• Inline entry modules are supported. (Can reduce bundle size and improve performance.)
• Performance configuration options are available. (Allows users to fine-tune Rspack’s performance characteristics.)

Fixes Worth Knowing

• Fixed issues with Module Federation runtime and data URIs. (Addresses compatibility and functionality for projects using Module Federation.)
• Corrected code splitting to be deterministic. (Ensures consistent build outputs.)
• Fixed memory leaks related to dependencies. (Improves stability and resource usage.)

Before You Upgrade

• Review your code for usage of the deprecated Compiler, MultiCompiler, and Compilation APIs and plan for migration to newer alternatives.
• Test thoroughly after updating SWC to ensure compatibility with your existing configuration.