feat(ecs/zipper): add more typing in order to strenghen types

Author: MartinFillon

example/pong/src/collisions.ts

@@ -1,8 +1,8 @@
-import { type ECSRegistry } from "@nanoforge/ecs";
+import { type Registry } from "@nanoforge/ecs";
 
 import { Hitbox, Position } from "./components";
 
-export function checkCollisions(registry: ECSRegistry, entity: any) {
+export function checkCollisions(registry: Registry, entity: any) {
   const entities = registry.getZipper([Hitbox, Position]);
 
   const { x, y } = entity.Position;

example/pong/src/systems.ts

@@ -1,5 +1,5 @@
 import { type Context } from "@nanoforge/common";
-import { type ECSRegistry } from "@nanoforge/ecs";
+import { type Registry } from "@nanoforge/ecs";
 import { type InputLibrary } from "@nanoforge/input";
 import { type SoundLibrary } from "@nanoforge/sound";
 
@@ -14,7 +14,7 @@ import {
   Velocity,
 } from "./components";
 
-export function move(registry: ECSRegistry) {
+export function move(registry: Registry) {
   const entities = registry.getZipper([Bounce, Position, Velocity]);
 
   entities.forEach((entity) => {
@@ -23,7 +23,7 @@ export function move(registry: ECSRegistry) {
   });
 }
 
-export function bounce(registry: ECSRegistry, ctx: Context) {
+export function bounce(registry: Registry, ctx: Context) {
   const entities = registry.getZipper([Bounce, Position, Velocity]);
 
   entities.forEach((entity) => {
@@ -39,7 +39,7 @@ export function bounce(registry: ECSRegistry, ctx: Context) {
   });
 }
 
-export function controlPlayer(registry: ECSRegistry, ctx: Context) {
+export function controlPlayer(registry: Registry, ctx: Context) {
   const entities = registry.getZipper([Controller, Position, Hitbox, Velocity]);
 
   entities.forEach((entity) => {
@@ -62,7 +62,7 @@ export function controlPlayer(registry: ECSRegistry, ctx: Context) {
   });
 }
 
-export function drawCircle(registry: ECSRegistry) {
+export function drawCircle(registry: Registry) {
   const entities = registry.getZipper([CircleComponent, Position]);
 
   entities.forEach((entity) => {
@@ -71,7 +71,7 @@ export function drawCircle(registry: ECSRegistry) {
   });
 }
 
-export function moveRectangle(registry: ECSRegistry) {
+export function moveRectangle(registry: Registry) {
   const entities = registry.getZipper([RectangleComponent, Position, Hitbox]);
 
   entities.forEach((entity) => {

packages/ecs/lib/libecs.d.ts

@@ -43,11 +43,18 @@ type Component = {name: string, [key: string]: any};
 
 type System = (registry: Registry, ctx: any) => void;
 
+type ComponentNames<T extends Component[]> = T extends [infer First, ...infer Rest] ? First["name"] | ComponentNames<Rest> : never;
+
+type ComponentForName<T extends Component[], N extends string> = T extends [infer First, ...infer Rest] ? First["name"] extends N ? First : ComponentForName<Rest, N> : never;;
+
+type ZipperResult<T extends Component[]> = { [K in ComponentNames<T>]: ComponentForName<T, K extends string ? K : never>; };;
+
 export interface Registry extends ClassHandle {
   registerComponent(_0: Component): SparseArray;
   getComponentsConst(_0: Component): SparseArray;
   getComponents(_0: Component): SparseArray;
   spawnEntity(): Entity;
+  getZipper<T extends Component[]>(_0: [...T]): ZipperResult<T>;
   killEntity(_0: Entity): void;
   clearEntities(): void;
   removeComponent(_0: Entity, _1: Component): void;
@@ -60,7 +67,6 @@ export interface Registry extends ClassHandle {
   getEntityComponent(_0: Entity, _1: Component): any | undefined;
   addComponent(_0: Entity, _1: Component): any | undefined;
   runSystems(_0: any): void;
-  getZipper(_0: Component[]): any;
 }
 
 interface EmbindModule {

packages/ecs/wasm/Registry.cpp

@@ -19,12 +19,28 @@
 
 namespace nfo {
     EMSCRIPTEN_DECLARE_VAL_TYPE(System);
+    EMSCRIPTEN_DECLARE_VAL_TYPE(ComponentNames);
+    EMSCRIPTEN_DECLARE_VAL_TYPE(ComponentForName);
+    EMSCRIPTEN_DECLARE_VAL_TYPE(ZZ)
 
     EMSCRIPTEN_BINDINGS(Registry)
     {
         emscripten::register_type<Component>("Component", "{name: string, [key: string]: any}");
         emscripten::register_type<System>("System", "(registry: Registry, ctx: any) => void");
-        emscripten::register_type<ZipperInput>("Component[]");
+        emscripten::register_type<ZipperInput>("[...T]");
+        emscripten::register_type<ComponentNames>(
+            "ComponentNames<T extends Component[]>", "T extends [infer First, ...infer Rest] ? First[\"name\"] | ComponentNames<Rest> : never"
+        );
+        emscripten::register_type<ComponentForName>(
+            "ComponentForName<T extends Component[], N extends string>",
+            "T extends [infer First, ...infer Rest] ? First[\"name\"] extends N ? First : ComponentForName<Rest, N> : never;"
+        );
+
+        emscripten::register_type<ZZ>(
+            "ZipperResult<T extends Component[]>", "{ [K in ComponentNames<T>]: ComponentForName<T, K extends string ? K : never>; };"
+        );
+
+        emscripten::register_type<ZipperOutput>("ZipperResult<T>");
 
         emscripten::class_<Registry>("Registry")
             .constructor()
@@ -55,7 +71,7 @@ namespace nfo {
             .function("runSystems", &Registry::run_systems)
             .function("removeSystem", &Registry::remove_system)
             .function("clearSystems", &Registry::clear_systems)
-            .function("getZipper", &Registry::get_zipper)
+            .function("getZipper<T extends Component[]>", &Registry::get_zipper)
             .function("maxEntities", &Registry::max_entities);
     }
 } // namespace nfo

packages/ecs/wasm/Registry.hpp

@@ -180,7 +180,7 @@ namespace nfo {
             return _next_entity;
         }
 
-        emscripten::val get_zipper(const ZipperInput &comps)
+        ZipperOutput get_zipper(const ZipperInput &comps)
         {
             if (!comps.isArray())
                 throw std::runtime_error("getZipper: need an array of comps as parameter");
@@ -207,7 +207,7 @@ namespace nfo {
                 if (need_to_add)
                     arr.set(idx, obj);
             }
-            return arr;
+            return ZipperOutput(arr);
         }
 
       private:

packages/ecs/wasm/Utils.hpp

@@ -22,6 +22,7 @@
 EMSCRIPTEN_DECLARE_VAL_TYPE(Component);
 EMSCRIPTEN_DECLARE_VAL_TYPE(ComponentArray);
 EMSCRIPTEN_DECLARE_VAL_TYPE(ZipperInput);
+EMSCRIPTEN_DECLARE_VAL_TYPE(ZipperOutput);
 
 std::optional<std::string> json_to_str(const emscripten::val &c);
 std::optional<emscripten::val> get_js_member(const emscripten::val &c, const std::string &member);