Emulator apple1js

apple1js — Apple I

The Apple I bundle is Will Scullin's apple1js — same author as the Apple ][+ bundle, written in the same style. Smaller machine, smaller bundle, smaller surface for things to go wrong.

Where we started

apple1js is pure JavaScript, no WASM, BSD-2-clause-style permissive licence (the actual SPDX header is a custom Will Scullin notice — see ATTRIBUTION). Boots to the Woz Monitor prompt, optionally drops into Integer BASIC, Applesoft, or VolksForth depending on what tape is loaded.

The runtime-tape design

apple1js's tapes/ directory holds 14 .js files. Ten of them are games; the other four — applesoft.js, basic.js, monitor.js, volksforth.js — are runtime dependencies (Integer BASIC, Applesoft BASIC, Woz Monitor, VolksForth) that play.html loads even in prompt mode. They look like orphan tapes if you only count games. They aren't.

This is the one situation where a file-count audit needs context. The post-bundle audit memory flags this explicitly so future passes don't try to "clean up" the BASIC implementations.

The chrome cleanup

Like apple2js, upstream apple1js.html ships a full app: keyboard buttons, modal dialogs, status panels. Same approach as the Apple ][+ bundle — keep the DOM intact (the bundle queries it at boot and throws if anything's missing), hide it with CSS:

h1, h2, .inset, .modal, #keyboard { display: none !important; }
td > div:not(.overscan) { display: none !important; }
.overscan {
  width: min(100vw, calc(100dvh * 4 / 3));
  height: min(100dvh, calc(100vw * 3 / 4));
}

Result: just the text display, scaled to 4:3.

How tapes launch

?game=<key> maps to a tape descriptor in the tapes object. apple1js's load API handles the rest — the tape script defines tapes[key] with the bytes inline, and the emulator's tape input mode reads them at the speed real cassette tape did. Most games take a few seconds to load.

Bundle layout

systems/apple1/
├── play.html         ← chrome hider + tape loader
├── controls.html     ← Woz Monitor / Integer BASIC reference
├── apple1.js         ← upstream entry
├── css/apple1.css
├── tapes/
│   ├── basic.js, applesoft.js, monitor.js, volksforth.js  ← runtime deps
│   └── <10 game tape .js files>

Related

• Emulator-apple2js — same author, sibling bundle
• Emulators — index