Logic Nodes

A free online logic gate simulator, hand-written in TypeScript on an HTML5 canvas.

Try it: nodes.kriyak.com, no account, no install. New here? Start at the about page.

Features

Simulation:

• AND, OR, NOT, XOR, NOR, and NAND gates
• Clock, delay, counter, button, toggle, and display nodes for time-dependent circuits
• Tick-based propagation, so feedback circuits (SR latches and friends) behave deterministically

Algebra:

• Truth table generation from any circuit
• Boolean expression generation, with optional simplification (requires a Wolfram Alpha App ID)
• The reverse direction too: construct a circuit from a boolean expression or a filled-in truth table

Editor:

• Custom nodes: package any circuit into a reusable component
• Pan, zoom to cursor, undo/redo, copy/paste, layers, and a minimap (ctrl+m)
• Keyboard shortcuts (ctrl+? for the overview)
• Save/load in the browser (localStorage), file import/export, and circuits encoded into the URL for sharing
• Built-in examples, including a working calculator

Development

pnpm install
pnpm dev      # start the dev server
pnpm build    # production build
pnpm test     # playwright tests

The whole editor is hand-written: rendering happens on a canvas with no diagramming library, and only the menus use Svelte. The interesting parts (viewport culling, high-DPI handling, hitboxes, the tick system) live in src/nodesystem/. I wrote up the lessons from building it here: Hand-writing a canvas node editor in TypeScript.

About

Built by Sem, a freelance software developer. There's a short project page on my site as well.

Licensed under Apache 2.0.