loader-runner is a small utility that runs webpack loaders via the `runLoaders` function. It helps execute a chain of loaders for a given resource and provides options like custom `readResource` or `processResource`, returning loader results (content, optional source maps, and metadata) plus dependency information.
Project status
- Maintenance status: Upstream is marked archived, which suggests it is not actively maintained in the usual sense, even though there were recent updates (last upstream push 2026-05-15).
- Update cadence: After a long gap (v4.3.0 in 2022-04-12), updates resumed with v4.3.1 in 2025-10-08 and v4.3.2 in 2026-04-24, roughly 6 months apart.
AI summary generated
Recent updates
v4.3.2
v4.3.2 is primarily described as a performance-focused release. The code changes show multiple internal efficiency improvements (iteration instead of recursion, faster UTF-8 BOM handling, and optimized request escaping), plus some behavior adjustments around loader context/request handling.
v4.3.1
v4.3.1 contains a small correctness fix related to empty resource requests and a performance-focused change to how the loader runner parses resource identifiers. Most of the runtime work is concentrated in lib/LoaderRunner.js and a smaller refactor in lib/loadLoader.js.
v4.3.0
Release v4.3.0 updates loader-runner to support returning multiple arguments from the user-provided options.processResource hook. Instead of assuming the callback returns only (err, buffer), the implementation forwards any additional callback arguments into the subsequent loader execution pipeline.
Featuresv4.2.0
v4.2.0 introduces a new `processResource` option to let consumers customize how the resource is read and how dependencies are registered during loader execution. It also updates the project CI setup from Travis to GitHub Actions and refreshes documentation around `runLoaders` options and result metadata.
Featuresv4.1.0
v4.1.0 primarily introduces improved handling for `#` in resource and loader request strings. Code changes show that requests are now parsed into path, query, and fragment components, and those components are exposed to loader execution context.
Featuresv2.4.0
v2.4.0 is a focused bugfix release. It improves loader export handling, fixes error reporting behavior to avoid throwing, and resolves a promise rejection callback being invoked twice.
v3.0.0
This release (v3.0.0) modernizes loader-runner to require Node.js 6+, removes the legacy System.import-based loader loading path, and changes how pitching results are interpreted when they are undefined. It also includes several error-handling and Promise/pitch control-flow fixes, including avoiding deprecated Buffer constructors.
Breaking