feat: ability to set entity as not damaging other entity

common/combat/damaging.trait.js

@@ -20,6 +20,7 @@ export class Damaging extends Trait {
   constructor(entity, params, state) {
     super(entity, params, state);
     this._collidingWith = [];
+    this._doesNotDamage = [];
     const damageSpecsJSON = this.params.damageSpecs;
     this._damageSpecs = damageSpecsJSON.map((damageSpec) => {
       return {
@@ -33,6 +34,10 @@ export class Damaging extends Trait {
     this._damagingSound = this.params.damagingSound;
   }
 
+  doesNotDamageEntity(entity) {
+    return -1 !== this._doesNotDamage.indexOf(entity);
+  }
+
   get damageSpecs() {
     return this._damageSpecs;
   }
@@ -41,11 +46,33 @@ export class Damaging extends Trait {
     return this._damagingSound;
   }
 
+  methods() {
+    return {
+
+      setDoesDamage: (entity) => {
+        const index = this._doesNotDamage.indexOf(entity);
+        if (-1 !== index) {
+          this._doesNotDamage.splice(index, 1);
+        }
+      },
+
+      setDoesNotDamage: (entity) => {
+        if (-1 === this._doesNotDamage.indexOf(entity)) {
+          this._doesNotDamage.push(entity);
+        }
+      },
+
+    };
+  }
+
   tick(elapsed) {
     if (AVOCADO_SERVER) {
       const isCollidingWith = this.entity.isCollidingWith;
       for (let i = 0; i < isCollidingWith.length; i++) {
         const entity = isCollidingWith[i];
+        if (this.doesNotDamageEntity(entity)) {
+          continue;
+        }
         if (entity.is('vulnerable')) {
           if (!entity.isInvulnerable) {
             entity.takeDamageFrom(this.entity);