pscript

What it is and what it does

PScript is a Python-to-JavaScript compiler that translates a carefully defined subset of Python into executable JavaScript. It was originally built as part of the Flexx framework and now stands as a standalone tool. The compiler takes Python functions and classes and outputs equivalent JavaScript code, allowing developers to write browser-facing code using Python syntax and semantics.

The package is pure Python with no external dependencies, making installation trivial. It targets modern browsers (Firefox, Chrome, Edge) and Internet Explorer 9 and above, though some newer Python constructs like async/await do not work in older browsers. The generated JavaScript handles Python-specific features like default arguments and prints to the browser console. It is actively maintained and used in production projects like TimeTagger.app.

Use it for:

• Build interactive web frontends where you want to write client-side logic in Python rather than JavaScript.
• Compile Python functions to JavaScript for use in web applications or browser-based tools.
• Develop Flexx-based applications that automatically transpile Python UI code to run in the browser.
• Create hybrid Python/JavaScript projects where business logic can be shared or ported between server and client.
• Prototype browser interactions and DOM manipulation using Python syntax before or instead of learning JavaScript.

Worth the install?

AI-flagged interpretation of the facts on this page — verify before relying

PScript compiles a Python subset to JavaScript, enabling you to write browser-facing code in Python syntax instead of JavaScript.

Yes, if you need to write browser code in Python. The package has no dependencies, installs cleanly, is actively maintained, and solves a real problem for teams that prefer Python syntax. The main gotcha is that only a Python subset compiles—you need to verify your code will translate before committing to this approach.

Install

pscript on PyPI

pip install pscript

uv add pscript

poetry add pscript

Installing pscript

Before you install

Installation is straightforward: the package is pure Python with no runtime dependencies, distributed as a wheel, and requires Python 3.8 or later. The project is actively maintained with a recent release.

Quickstart

from pscript import py2js

def foo(a, b=2):
    print(a - b)

print(py2js(foo))

Requires Python 3.8 or later; only a subset of Python syntax is supported (not all Python features compile to JavaScript).

Verify before relying

• Exact scope of Python subset supported (which language features compile and which do not)
• Performance characteristics of generated JavaScript compared to hand-written code
• Browser compatibility details beyond the stated modern-browser and IE9+ support

Package facts

Evidence: pscript-0.8.1-py3-none-any.whl

Keywords: Python, JavaScript, compiler, transpiler, parser

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