Bun started out with npm compatibility as a key requirement, so has a very npm-like package manager from the beginning. Deno at first tried to focus only on we

Bun started out with npm compatibility as a key requirement, so has a very npm-like package manager from the beginning. Deno at first tried to focus only on web-like/browser-like package management with a focus on full URLs ("https://mypackage.example.com/v2/mypackage.js https://mypackage.example.com/v2/mypackage.js") and importmaps (a JSON file mapping "mypackage" to a URL such as the previous example) and package/file caching over installing. Deno 2 made Node-compatibility a higher priority (partly because of Bun's competition, partly because of complaints that Deno was hard to migrate to piecemeal from existing Node codebases) and one of those initiatives was a more npm-compatible package manager out of the box (that can also speak Node package.json and manage a node_modules directory), even as Deno still encourages for greenfield projects the URL/importmap/caching approach (with the expansion that it also understands `npm:` pseudo-URLs, `jsr:` pseudo-URLs [an alternative package registry with a stronger focus on ESM and Typescript types], and `node:` pseudo-URLs [emulated node internals], beyond just browser-safe `http:` and `https:` URLs).