Exploring Deno 2 and Bun as Modern JavaScript Package Managers

Deno

Deno 2, the latest version of the secure JavaScript/TypeScript runtime created by Node.js founder Ryan Dahl, now supports full backward compatibility with Node and npm, allowing it to run existing Node projects and gradually adopt Deno’s integrated toolchain, including using Deno as a standalone JavaScript package manager.

Dependency Sources

Deno can install modules from npm, the new JSR registry, or directly via URLs, and it also supports monorepo management, making it easy to integrate code from multiple sources without compatibility concerns.

JSR: Deno’s new JavaScript registry, similar to npm, available at https://jsr.io/ .

Commands

Deno 2 understands package.json and node_modules and adds three key sub‑commands for dependency management:

deno install : installs all dependencies listed in the configuration file, analogous to npm install .

deno remove : removes dependencies from deno.json or package.json .

deno add : adds a dependency to deno.json or package.json , handling npm or JSR packages appropriately.

Performance

Deno optimizes storage and speed by using hard links on Linux and clonefile on macOS, reducing duplicate copies and speeding up installations, especially in monorepos.

Benchmarks from the Deno team show deno install is 15 % faster than npm install without cache and up to 90 % faster with cache, even surpassing Bun.

New Features

Additional commands such as deno update and deno outdated further enhance Deno’s package‑management capabilities.

Bun

Bun, the fast all‑in‑one JavaScript runtime that gained rapid popularity, can also be used solely as a JavaScript package manager, offering strong Node.js compatibility, workspace support, global install caching, optimized file writes, familiar APIs, a binary lock file, and default security measures that limit arbitrary post‑install scripts.

Key Characteristics

Node.js compatibility : works with projects containing package.json , supporting workspaces, Git/HTTP/tarball dependencies, and custom registries.

Workspace support : reads workspaces from package.json and installs all workspace packages in one go.

Global install cache : caches downloaded packages globally to avoid redundant downloads.

Optimized file writes : uses the fastest OS system calls for writing files from the cache, outperforming tools like pnpm.

Familiar API : commands resemble npm/pnpm/yarn for adding, removing, or installing dependencies.

Binary lock file : creates a binary bun.lockb that parses faster than JSON/YAML lock files.

Default security : disables arbitrary post‑install scripts; privileged dependencies can be whitelisted via privilegedDependencies in package.json .

Performance tests supplied by Bun show it outperforms other popular JavaScript package managers when a cache is present.