feat: component add/remove

packages/ecs/src/ecs.js

@@ -59,6 +59,22 @@ export default class Ecs {
         return source;
       }
 
+      insertComponents(entity, components) {
+        this.ecs.insert(entity, components);
+      }
+
+      insertManyComponents(components) {
+        this.ecs.insertMany(components);
+      }
+
+      removeComponents(entity, components) {
+        this.ecs.remove(entity, components);
+      }
+
+      removeManyComponents(entities) {
+        this.ecs.removeMany(entities);
+      }
+
     }
     const wrappedSystem = new WrappedSystem(this.Components);
     wrappedSystem.reindex(Object.keys(this.$$entities));
@@ -192,6 +208,10 @@ export default class Ecs {
     }
   }
 
+  destroy(entity) {
+    this.destroyMany([entity]);
+  }
+
   destroyAll() {
     this.destroyMany(Object.keys(this.$$entities).map((entity) => BigInt(entity)));
   }
@@ -327,6 +347,27 @@ export default class Ecs {
     }
   }
 
+  remove(entity, components) {
+    this.removeMany([[entity, components]]);
+  }
+
+  removeMany(entities) {
+    const removing = {};
+    for (let i = 0; i < entities.length; i++) {
+      const [entity, components] = entities[i];
+      for (let j = 0; j < components.length; j++) {
+        const component = components[j];
+        if (!removing[component]) {
+          removing[component] = [];
+        }
+        removing[component].push(entity);
+      }
+    }
+    for (const component in removing) {
+      this.Components[component].destroyMany(removing[component]);
+    }
+  }
+
   removeSystem(SystemLike) {
     const index = this.$$systems.findIndex((system) => SystemLike === system.source);
     if (-1 !== index) {

packages/ecs/test/ecs.js

@@ -48,6 +48,14 @@ it('can create entities with components', () => {
     .to.deep.equal(JSON.stringify({Empty: {}, Position: {x: 32, y: 420, z: 0}}));
 });
 
+it("can remove entities' components", () => {
+  const ecs = new Ecs({Empty, Position});
+  const entity = ecs.create({Empty: {}, Position: {y: 420}});
+  ecs.remove(entity, ['Position']);
+  expect(JSON.stringify(ecs.get(entity)))
+    .to.deep.equal(JSON.stringify({Empty: {}}));
+});
+
 it('can get entities unsafely', () => {
   const ecs = new Ecs({Empty, Position});
   const entity = ecs.create({Empty: {}, Position: {y: 420}});
@@ -142,6 +150,35 @@ it('can schedule entities to be deleted when ticking systems', () => {
     .to.be.undefined;
 });
 
+it('can add components to and remove components from entities when ticking systems', () => {
+  const Foo = {bar: 'uint8'};
+  const ecs = new Ecs({Foo});
+  class AddComponent extends System {
+
+    tick() {
+      this.insertComponents(1n, {Foo: {}});
+    }
+
+  }
+  class RemoveComponent extends System {
+
+    tick() {
+      this.removeComponents(1n, ['Foo']);
+    }
+
+  }
+  ecs.addSystem(AddComponent);
+  ecs.createExact(1);
+  ecs.tick(1);
+  expect(ecs.get(1).Foo)
+    .to.not.be.undefined;
+  ecs.removeSystem(AddComponent);
+  ecs.addSystem(RemoveComponent);
+  ecs.tick(1);
+  expect(ecs.get(1).Foo)
+    .to.be.undefined;
+});
+
 it('can encode and decode an ecs', () => {
   const ecs = new Ecs({Empty, Position});
   const entity = ecs.create({Empty: {}, Position: {y: 420}});