affected vs Changesets

affected is a free, MIT-licensed command-line tool for identifying monorepo packages touched by Git changes and running tests or other commands on those packages. It traces transitive dependencies and can explain the chain from a change to an affected package. The README says it detects project type and dependency graph automatically to get started without configuration. Supported ecosystems include Cargo, npm, pnpm, Yarn, Bun, Go, Python, Maven, Gradle, .NET, Swift, Dart/Flutter, Elixir, and Scala/sbt. CLI commands cover listing packages, testing, running commands, viewing graphs, CI, initialization, and watch mode. Execution options include parallel jobs, dry-run previews, timeouts, package filters, and skip patterns. Outputs include JSON, JUnit XML, CI formats, shell completions, dependency trees, and DOT graphs. GitHub Actions support includes a setup action and dynamic job matrices; a companion action can post and update pull request comments with affected packages and reasons. Installation options include Homebrew, Python and language package managers, GitHub Actions, and release binaries. It runs on Linux, macOS, and Windows.

Changesets has no write-up on Specifiction yet; its figures are above.