Bun vs JSPM

Bun combines a JavaScript runtime, package manager, test runner, and bundler in one binary. It runs JavaScript and TypeScript on JavaScriptCore, with support for Node.js APIs and node_modules. Its npm-compatible package manager supports workspaces, catalogs, overrides, patches, readable lockfiles, private registry authentication, dependency resolution, and offline installation. The test runner includes Jest-compatible expectations, mocks, snapshots, DOM testing, and coverage. For builds, Bun handles TypeScript, JSX, CSS, and HTML for browsers and servers, and includes a development server with hot module reloading and single-file executables. Built-in APIs cover PostgreSQL, MySQL, SQLite, Redis, S3-compatible storage, HTTP, and WebSockets. The project names Next.js, Remix, Nuxt, Astro, SvelteKit, Hono, and Elysia among frameworks that run on Bun. It is MIT-licensed and developed publicly on GitHub. Bun runs on Linux, macOS, and Windows, subject to minimum OS versions and x64 processors with SSE4.2. Install options include an official script, npm, Homebrew, Windows package managers, and Docker. Support and discussion are available through Discord.

JSPM is an open-source project for managing browser dependencies through import maps. Its CLI is the main package-management tool for import maps, while the jspm.io CDN loads optimized npm dependencies directly, without a separate build step. The development server can install packages automatically, hot-reload, and strip TypeScript types. For production, jspm build uses RollupJS to bundle package entry points and dependencies. JSPM supports native ES modules and standards-based browser workflows, and can add Subresource Integrity hashes across an application's static and dynamic module graph. Built-in providers include jspm.io, nodemodules, esm.sh, unpkg, skypack, and jsdelivr; custom providers can also be configured. Integrations include an online generator, VSCode web extension, Vite plugin, experimental Node.js loader, Import Map Rails, and Symfony AssetMapper. The hosted API generates import maps and dependency graphs, though JSPM recommends running its Generator library directly when possible. Import maps are supported in recent Firefox, Safari, and Chrome, and in Deno. The project costs nothing; CDN services are described as free and donation-supported. Its publish command is experimental and has no reliability guarantees for publishing on jspm.io.