deno vs node

deno

This is the Deno runtime monorepo — a Rust workspace (~80 crates) that builds a JavaScript/TypeScript/WebAssembly runtime on V8 and Tokio, plus the `deno` CLI that wraps it with a package manager, type checker, formatter, linter, test runner, LSP server, and single-file-binary compiler. The distinctive shape is three layers: `libs/` holds vendored foundational crates (notably `deno_core` v0.412.0 at `libs/core`, the op2 proc-macro at `libs/ops`, and a hand-rolled zero-allocation flag parser at `libs/cli_parser` that replaced clap with `const` command tables), `ext/` holds 32 self-contained extension crates that expose native ops to JS, and `runtime/`+`cli/` assemble them into the shipped binary. Everything user code touches passes through a capability permission system (`runtime/permissions/lib.rs`, ~11.7k lines) that gates read/write/net/env/sys/run/ffi/import, and the CLI is built around a lazily-memoised dependency-injection container (`CliFactory`) so that `deno fmt` never pays for the npm resolver. It targets JS/TS application developers and, increasingly, Node.js users — a large fraction of `ext/node` exists purely for npm/Node compatibility.

node

This is the Node.js runtime itself at v26.10.0 — a C++/V8 host (src/, ~495 files) wrapping a JavaScript standard library (lib/, ~429 files) that is compiled into a V8 startup snapshot at build time. Beyond upstream-familiar surface, this tree carries several large experimental subsystems wired through the same plumbing: a `node:vfs` virtual file system that intercepts `node:fs` and the module loaders at reserved mount points under `os.devNull/vfs/<id>`, a `node:ffi` libffi-backed foreign function interface gated by a `kFFI` permission scope, a `node:dtls` endpoint/session stack, a `node --experimental-bench` benchmark runner mirroring the test runner, and a vendored Rust crate set (`deps/crates`, temporal_rs + ICU) linked as a staticlib. The audience is Node core collaborators; the distinctive engineering property is that every new capability is a triple — a CLI option in `src/node_options.cc`, a `setupX()` in `pre_execution.js` that calls `BuiltinModule.allowRequireByUsers()`, and an internal binding registered in `src/node_binding.h`.

deno

The binary entry is a nine-line `cli/main.rs` that delegates to `deno::main()` in `cli/lib.rs`, which parses flags, initialises V8, and dispatches a `DenoSubcommand` to a handler under `cli/tools/`. Shared services are constructed lazily through `CliFactory`, a container of `Deferred<T>` once-cells covering caches, resolvers, the file fetcher, npm installer, type checker, and permission container. The JS runtime is assembled in `runtime/worker.rs::common_extensions`, which registers ~35 extension crates from `ext/` in a strict, snapshot-sensitive order; a V8 startup snapshot is baked at build time by `cli/snapshot/build.rs`. Storage is the DENO_DIR: SQLite caches (`cli/cache/caches.rs`) for dep analysis, type checking, code cache, fast-check, and lint/fmt incremental state, plus an HTTP cache and npm package cache. Builds run through `cargo`/`./x`, CI is generated TypeScript (`.github/workflows/ci.ts` → `ci.generated.yml`), and the deployment shape is a single statically-linked executable distributed per-platform.

node

Execution begins in `src/node_main.cc` (`main`/`wmain`) which calls `node::Start`, which after SEA argv fixup loads the V8 startup snapshot and runs a `NodeMainInstance`. C++ then picks exactly one main script from `lib/internal/main/` via a linear dispatch in `src/node.cc`; that script calls into `lib/internal/process/pre_execution.js` to configure the realm before user code. The JS layer talks to C++ only through `internalBinding()`, whose registry is the `NODE_BUILTIN_*_BINDINGS` macro list in `src/node_binding.h`. Build is GYP/Make (`configure.py` → `node.gyp` → `Makefile`) with a secondary GN path, plus Cargo for `deps/crates`. There is no deployment target in the usual sense: the artifact is the `node` binary, optionally repackaged as a single executable application by `src/node_sea.cc`.

deno

• tests/ — 1720 files
• libs/ — 801 files
• ext/ — 752 files
• cli/ — 517 files
• runtime/ — 74 files
• tools/ — 69 files
• .github/ — 32 files
• doc/ — 7 files

node

• test/ — 863 files
• deps/ — 863 files
• benchmark/ — 637 files
• src/ — 495 files
• lib/ — 429 files
• tools/ — 391 files
• doc/ — 162 files
• .github/ — 60 files