ESM Unit vs Jest
ESM Unit
github.com
Jest
jestjs.ioSide by side
| Figure | ESM Unit | Jest |
|---|---|---|
| Price from | — | Free |
| Free plan | — | Yes |
| Free trial | — | — |
| Open source | — | — |
| Web | Yes | — |
| Self-hosted | — | Yes |
| Plans published | 0 | 1 |
| Spec score · JavaScript Testing Frameworks | 7.3 (#15) | 7.7 (#8) |
| Coverage | It supports per-file code coverage reports and configurable coverage thresholds. | The site says Jest can collect project code coverage, including from untested files, with the --coverage flag. |
| Integrations | The README recommends Sinon for stubbing, mocking, and assertions against mocks. | The guide documents use with webpack and Parcel, and says Jest is not supported by Vite because of plugin system incompatibilities. |
| Intended users | The stated use case is developers who need to unit test native ECMAScript modules in web browsers. | The site describes Jest as designed to ensure correctness across any JavaScript codebase. |
| Purpose | ESM Unit is a unit testing tool for native ECMAScript modules in web browsers. | Jest is a JavaScript testing framework focused on simplicity and correctness. |
| Support | The project README invites users to open an issue or pull request and says it welcomes contributions. | The site points users to Stack Overflow, Reactiflux, and Twitter for community help. |
| Watch mode | The --watch option reruns tests when files change, and cannot be used at the same time as --debug. | The repository describes an interactive watch mode that runs test files related to changed files. |
Plans
In their own words
Jest
Jest is a free, self-hosted JavaScript testing framework focused on checking correctness. It supports projects using Babel, TypeScript, Node, React, Angular, Vue and other technologies, and aims to run without configuration on most JavaScript projects. Snapshot tests compare rendered output with a saved reference. Tests run in separate processes for parallel execution, while the --coverage flag can collect coverage, including from files without tests. Mock functions and a custom import resolver support replacing objects and observing calls. Interactive watch mode reruns tests related to changed files. Installation guidance covers npm, Yarn, pnpm and Bun. Documentation describes webpack and Parcel use, but states that Vite is unsupported because of plugin-system incompatibilities. With Babel handling TypeScript, Jest transpiles tests without type-checking them during execution. A free plan is listed at free, with no paid plans or usage limits stated.