Lint

Setup

@moku-labs/game/lint is an oxlint JS plugin named moku-game. The rules use the ESLint rule API, so ESLint loads the same object. The engine ships no default severity: a game turns each rule on.

{
  "jsPlugins": ["@moku-labs/game/lint"],
  "rules": {
    "moku-game/lazy-imports": "error",
    "moku-game/native-imports": "error",
    "moku-game/dev-imports": "error",
    "moku-game/no-module-state": "error",
    "moku-game/determinism": "error",
    "moku-game/rules-siblings": "error",
    "moku-game/static-keys": "error",
    "moku-game/layer-imports": "error",
    "moku-game/feature-door": "error",
    "moku-game/sub-features": "error",
    "moku-game/test-suffix": "error"
  }
}

The engine rules

import { type A } from "pixi.js" is reported: under verbatimModuleSyntax it keeps a side-effect import, which loads Pixi. Write import type { A } from "pixi.js".

Static keys

The game reports a JSX key at run time, and the project index turns it back into the line that wrote it. That works when the key is written so the index can read it.

/** @jsxImportSource @moku-labs/game */
type Tab = "audio" | "language";

const tabKeys = { audio: "tabSound", language: "tabLanguage" };

export function TabButton(props: { tab: Tab }) {
  const key = tabKeys[props.tab];
  return <button key={key} intent="openTab" />;
}

/** @jsxImportSource @moku-labs/game */
type Tab = "audio" | "language";

export function TabButton(props: { id: string; tab: Tab }) {
  return <button key={props.id} intent="openTab" payload={{ tab: props.tab }} />;
}

export const soundTab = <TabButton id="tabSound" tab="audio" />;

The message is Keys: a JSX key must be a literal, a template, or props.id / props.<name>Key. Pass the key in as a prop: <X id="…">.

The layout rules

Four rules check a game on the layered layout. Each path below the game root sits in one layer:

A file outside them, such as kit.ts, nodes/ or web/, keeps the layout rules quiet. So a game on a flat layout lints as before.

A sub-feature never imports the feature it lives in: Door: a sub-feature does not import the feature it lives in: features/episodes/ep01 imports features/episodes. Move what they share into a sibling sub-feature, such as features/episodes/episodes-kit, and import it from its door.

Aliases

layer-imports, feature-door and rules-siblings read the compilerOptions.paths of the game's tsconfig.json, the way the project index does, extends included. Without paths they read the default table:

aliasTargetsOf(tsconfig, root, specifier) answers what the rules read for one specifier:

import { aliasTargetsOf } from "@moku-labs/game/lint";

aliasTargetsOf("/game/tsconfig.json", "/game", "@features/orders"); // ["/game/features/orders/index.ts"] for a game without a tsconfig

The * of @features/* crosses /: @features/episodes/ep01 is the door of a sub-feature.

Options

Every rule takes files and ignores. A key you give replaces that default. Globs are relative to the directory oxlint runs in.

{
  "rules": {
    "moku-game/determinism": ["error", { "files": ["src/logic/**"], "ignores": ["**/*.dev.ts"] }],
    "moku-game/layer-imports": ["error", { "root": "src", "tsconfig": "tsconfig.game.json" }],
    "moku-game/test-suffix": ["error", { "suffixes": { "tests/e2e/": ".spec.ts" } }]
  }
}

The logic, where determinism and native-imports look by default, is the root index.ts, **/state.ts, **/tables.ts, **/game.ts and **/{core,nodes,flows,rules,features,shared}/**. Tests (tests/**, **/__tests__/**, *.test.ts) are skipped by every rule but test-suffix.

Related

• Nodes & flows: the rules of determinism the lint enforces.
• Features: doors and sub-features.
• API reference: @moku-labs/game/lint and @moku-labs/game/project.