A collection of small personal tools and weekend builds. I use these to scratch a specific itch or test out an idea quickly, prioritizing functional utility over an over-engineered setup. You'll find a couple of exceptions here, like this portfolio, where the build is more deliberate and fully realized.
jsBASIC is a small BASIC interpreter that runs entirely in the browser. Write a
program with line numbers in the editor, click Run, and it executes in its own
runtime window, just like the old days (minus the beige keyboard).
It currently supports:
PRINT, LET, and INPUT
FOR / NEXT loops
IF ... THEN and GOTO
Arithmetic, comparison, and logical (AND, OR, NOT) expressions
A configurable instruction limit to keep runaway programs in check
It started as a quick experiment in building with AI agents, then became a
chance to clean up and harden the result by hand. Try it at
jsbasic.dev.
I scaffolded the MVP with AI coding agents, then refactored it by hand into a typed, modular interpreter with per-statement handlers, a hardened expression evaluator, and a React runtime window.
Challenges & Solutions
The interesting problem was running user programs safely in the browser. Expressions are parsed with jsep into an AST and evaluated against a whitelist of operators instead of using eval, and the interpreter yields to the event loop every few hundred steps with a configurable instruction limit, so an infinite GOTO loop can't freeze the tab. Programs run in a separate popup window that talks to the editor over origin-checked postMessage, with INPUT bridged back as a promise that resolves when the user answers.
The jsBASIC editorThe jsBASIC runtime
4.3.0Shipped a new internal refund platform, streamlining help desk process.
