Guidebook JS 01 Setup

JavaScript/TypeScript on gregCore is a full UI-focused SDK (Jint): per-mod engines, toasts, Toolkit panels, F1-hub binding, settings, hooks — plus HotLoad in the main menu. Read this page, then build Guidebook JS 02 Project.

Layout

One folder per mod (folder name = mod ID):

<game root>/UserData/gregCore/Mods/JS/<modId>/*.js

Write TypeScript against templates/js/greg.d.ts, compile with tsc, ship the emitted .js. Raw .ts files are skipped with a warning (no transpiler in the game). Each mod gets an isolated engine (16 MB cap).

The greg API

greg.log("hi"); greg.warn("careful"); greg.error("broken");
greg.toast("Done.", 3);
greg.toastRich("MYMOD", "Title", "sub line", 5);
greg.notify("Title", "Message", 5);

var panel = greg.createPanel("My Mod");   // chainable Toolkit builder
panel.AddHeadline("Hello");
panel.AddLabel("Status: ok.");
panel.AddButton("Ping", function () { greg.toast("pong", 2); });
panel.AddSecondaryButton("Close", toggle);
panel.Show(); // .Hide() / .Toggle() / ClearContent() for refresh

greg.bindMenu("mymod", toggle, isOpen);   // F1-hub wiring (one call)
greg.reportMenu("mymod", open);           // live state from hotkey paths

greg.registerToggle("enabled", "Enabled", true);
greg.registerSlider("rate", "Rate", 1.0);
greg.registerKey("toggle", "Toggle", toggle);

greg.on("greg.PLAYER.CoinChanged", function (p) { /* p.* */ });

Lifecycle (define when needed): onUpdate(dt), onSceneLoaded(name). A throwing callback is disabled after its first failure (no log spam).

HotLoad (main menu only)

Edit + save → queued (500 ms debounce) → applied on next main-menu entry (engine dropped, files re-executed). Never mid-game. Deleted mod folders unload. Manual trigger from any script context is not exposed — return to the menu.

Limits: only greg is a stable contract (no CLR patching, no Harmony from scripts — use hooks). No compiler on the machine means no scripts at all (check the bridge warning in the log).

Your first JS mod

UserData/gregCore/Mods/JS/hello/hello.js:

var count = 0;
greg.toast("hello loaded.", 3);
greg.on("greg.PLAYER.CoinChanged", function () {
    count += 1;
    if (count === 1 || count % 25 === 0)
        greg.toast("Coins changed x" + count + ".", 3);
});

Restart once (first discovery), then iterate without restarts via HotLoad. Verify: toast on start, toast every 25 coin events, no [gregCore][JS] errors.

Checkpoint

• Folder mod ID correct, toasts observed, coin counter works, no errors.
• You can name the UI calls (toast, createPanel, bindMenu) and the HotLoad rule (menu only, queued otherwise).

Next: Guidebook JS 02 Project — panel + settings + menu sample mod.