feat: migrate JavaScript files to TypeScript, enhancing type safety and maintainability across the codebase

src/systems/SkillEffectSystem.ts

@@ -0,0 +1,74 @@
+import { System } from '../core/System.ts';
+import { SystemName } from '../core/Constants.ts';
+import type { Entity } from '../core/Entity.ts';
+
+export interface SkillEffect {
+  lifetime: number;
+  time: number;
+  type?: string;
+  x?: number;
+  y?: number;
+  angle?: number;
+  range?: number;
+  coneAngle?: number;
+  caster?: Entity;
+  startX?: number;
+  startY?: number;
+  speed?: number;
+  onUpdate?: (deltaTime: number) => void;
+  onComplete?: () => void;
+}
+
+/**
+ * System responsible for tracking and updating temporary active skill effects like fire breath or pounce trails.
+ */
+export class SkillEffectSystem extends System {
+  activeEffects: SkillEffect[];
+
+  constructor() {
+    super(SystemName.SKILL_EFFECT);
+    this.requiredComponents = [];
+    this.priority = 50;
+    this.activeEffects = [];
+  }
+
+  /**
+   * Update all active effects, removing them when their lifetime expires.
+   * @param deltaTime - Time elapsed since last frame in seconds
+   * @param _entities - Filtered entities
+   */
+  process(deltaTime: number, _entities: Entity[]): void {
+    for (let i = this.activeEffects.length - 1; i >= 0; i--) {
+      const effect = this.activeEffects[i];
+      effect.lifetime -= deltaTime;
+      effect.time += deltaTime;
+
+      if (effect.onUpdate) {
+        effect.onUpdate(deltaTime);
+      }
+
+      if (effect.lifetime <= 0) {
+        if (effect.onComplete) {
+          effect.onComplete();
+        }
+        this.activeEffects.splice(i, 1);
+      }
+    }
+  }
+
+  /**
+   * Add a new visual skill effect to the system.
+   * @param effect - The effect data object
+   */
+  addEffect(effect: SkillEffect): void {
+    this.activeEffects.push(effect);
+  }
+
+  /**
+   * Get the list of currently active skill effects.
+   * @returns Array of active effects
+   */
+  getEffects(): SkillEffect[] {
+    return this.activeEffects;
+  }
+}