Sage.js

Open research mathematics, native to Node.

Sage.js is an experiment in building a genuinely useful open computer algebra system in the Node.js ecosystem. It combines:

• a lightweight Python-like language compiled to JavaScript;
• optional Sage-style mathematical syntax;
• V8's mature optimizing runtime;
• direct access to JavaScript and npm packages;
• native mathematical libraries through stable Node-API bindings.

The long-term goal is analogous to SageMath and OSCAR: integrate the best open mathematical libraries behind a coherent language, object model, coercion system, package distribution, and collection of high-level algorithms.

Version 0.1 is intentionally much smaller. It revives and modernizes the self-hosting language compiler formerly developed as JPython and PyLang. It does not yet contain the native mathematical library layer.

Install

Sage.js requires Node.js 20.17 or newer.

npm install --global @sagemath/sagejs

It can also be tried without a global installation:

npx --package @sagemath/sagejs sagejs

Sage mode

The sagejs command uses Sage-style syntax by default:

$ sagejs
Welcome to Sage.js [Node.js v26.5.0 on x64].
sage: 2^100
1.2676506002282294e+30
sage: sum([1..100])
5050
sage: 7^^3
4

In Sage mode:

• ^ means exponentiation;
• ^^ means bitwise xor;
• [a..b] means the inclusive range from a through b;
• numerical literals pass through the language's configurable number hook.

These features are implemented in the parser and compiler, not by textual preprocessing.

Run a file directly:

sagejs program.sage

Compile it without executing:

sagejs compile program.sage --output program.js

Python mode

Python mode retains Python's meaning of ^:

$ sagejs --python
Welcome to Sage.js (Python mode) [Node.js v26.5.0 on x64].
>>> 2^3
1
>>> 2**3
8

The sagepython executable is equivalent:

sagepython program.py
sagepython

This is a Python-like language, not an implementation of the complete Python language or standard library. Programs can directly load JavaScript packages with require(...), and compiled code runs as JavaScript rather than through CPython or WebAssembly.

JavaScript API

The compiler can also be loaded from Node:

const createCompiler = require("@sagemath/sagejs");
const compiler = createCompiler();
const ast = compiler.parse("print(2 + 3)");

The CLI can emit standalone JavaScript containing the small Sage.js base library:

sagejs --python compile input.py --output output.js
node output.js

Build from source

git clone https://github.com/sagemathinc/sagejs
cd sagejs
npm ci
npm test

npm run build compiles the TypeScript tooling and then uses the checked-in bootstrap compiler to rebuild the compiler from its Python-like source. The build continues until the compiler is compiled with an up-to-date version of itself.

See HACKING.md for the source layout.

Status

Sage.js 0.1 is a research prototype. Its existing language test suite is substantial, but Python compatibility is deliberately incomplete and exact integer semantics still need design work.

The next architectural milestone is a native Node-API package demonstrating efficient conversion between JavaScript BigInt and a serious mathematical library such as FLINT or PARI.

History and licensing

The language compiler descends from RapydScript-ng, JPython, and PyLang. The original copyright notices and permissive license are preserved in source headers and under licenses.

Sage.js as a whole is distributed under the GNU General Public License, version 3. This is appropriate for an open research mathematics system built around GPL-compatible mathematical libraries.