diff --git a/app/ecs/component.js b/app/ecs/component.js
index be65c84..b2c182d 100644
--- a/app/ecs/component.js
+++ b/app/ecs/component.js
@@ -134,11 +134,22 @@ export default class Component {
       $$entity = 0;
       destroy() {}
       initialize(values, defaults) {
+        const {properties} = concrete;
         for (const key in values) {
-          this[`$$${key}`] = values[key];
+          if (properties[key]?.$.set) {
+            properties[key].$.set(Component, this, `$$${key}`, values[key]);
+          }
+          else {
+            this[`$$${key}`] = values[key];
+          }
         }
         for (const key in defaults) {
-          this[`$$${key}`] = defaults[key];
+          if (properties[key]?.$.set) {
+            properties[key].$.set(Component, this, `$$${key}`, defaults[key]);
+          }
+          else {
+            this[`$$${key}`] = defaults[key];
+          }
         }
         Component.ecs.markChange(this.entity, {[Component.constructor.componentName]: values})
       }
@@ -146,7 +157,12 @@ export default class Component {
         const {properties} = concrete;
         const json = {};
         for (const key in properties) {
-          json[key] = this[key];
+          if (properties[key]?.$.json) {
+            json[key] = properties[key].$.json(this[key]);
+          }
+          else {
+            json[key] = this[key];
+          }
         }
         return json;
       }
@@ -160,9 +176,15 @@ export default class Component {
         return this.toFullJSON();
       }
       update(values) {
+        const {properties} = concrete;
         for (const key in values) {
-          if (concrete.properties[key]) {
-            this[`$$${key}`] = values[key];
+          if (properties[key]) {
+            if (properties[key]?.$.set) {
+              properties[key].$.set(Component, this, `$$${key}`, values[key]);
+            }
+            else {
+              this[`$$${key}`] = values[key];
+            }
           }
           else {
             this[key] = values[key];
@@ -186,7 +208,12 @@ export default class Component {
         },
         set: function set(value) {
           if (this[`$$${key}`] !== value) {
-            this[`$$${key}`] = value;
+            if (concrete.properties[key]?.$.set) {
+              concrete.properties[key].$.set(Component, this, `$$${key}`, value);
+            }
+            else {
+              this[`$$${key}`] = value;
+            }
             Component.markChange(this.entity, key, value);
           }
         },
diff --git a/app/ecs/components/alive.js b/app/ecs/components/alive.js
index 94e6ff0..fe47d03 100644
--- a/app/ecs/components/alive.js
+++ b/app/ecs/components/alive.js
@@ -19,8 +19,8 @@ export default class Alive extends Component {
         this.$$dead = true;
         const {Ticking} = ecs.get(this.entity);
         if (Ticking) {
-          this.$$death.locals.entity = ecs.get(this.entity);
-          const ticker = this.$$death.ticker();
+          this.deathScript.locals.entity = ecs.get(this.entity);
+          const ticker = this.deathScript.ticker();
           ecs.addDestructionDependency(this.entity.id, Ticking.add(ticker));
         }
       }
@@ -30,21 +30,11 @@ export default class Alive extends Component {
     if (0 === instance.maxHealth) {
       instance.maxHealth = instance.health;
     }
-    // heavy handed...
-    if ('undefined' !== typeof window) {
-      return;
-    }
-    instance.$$death = this.ecs.readScript(
-      instance.deathScript,
-      {
-        ecs: this.ecs,
-      },
-    );
   }
   static properties = {
     deathScript: {
       defaultValue: '/resources/misc/death-default.js',
-      type: 'string',
+      type: 'script',
     },
     health: {type: 'uint32'},
     maxHealth: {type: 'uint32'},
diff --git a/app/ecs/components/behaving.js b/app/ecs/components/behaving.js
index ac3c64a..540b117 100644
--- a/app/ecs/components/behaving.js
+++ b/app/ecs/components/behaving.js
@@ -16,10 +16,6 @@ export default class Behaving extends Component {
     };
   }
   load(instance) {
-    // heavy handed...
-    if ('undefined' !== typeof window) {
-      return;
-    }
     for (const key in instance.routines) {
       instance.$$routineInstances[key] = this.ecs.readScript(instance.routines[key]);
     }
diff --git a/app/ecs/components/collider.js b/app/ecs/components/collider.js
index 0c6c2aa..de2ad20 100644
--- a/app/ecs/components/collider.js
+++ b/app/ecs/components/collider.js
@@ -9,8 +9,6 @@ export default class Collider extends Component {
     return class ColliderInstance extends super.instanceFromSchema() {
       $$aabb = {x0: Infinity, x1: -Infinity, y0: Infinity, y1: -Infinity};
       $$aabbs = [];
-      $$collisionStart;
-      $$collisionEnd;
       $$intersections = new Map();
       get aabb() {
         const {Position: {x: px, y: py}} = ecs.get(this.entity);
@@ -77,8 +75,8 @@ export default class Collider extends Component {
             }
           }
           if (!hasMatchingIntersection) {
-            if (this.$$collisionStart) {
-              const script = this.$$collisionStart.clone();
+            if (this.collisionStartScript) {
+              const script = this.collisionStartScript.clone();
               script.locals.entity = thisEntity;
               script.locals.other = otherEntity;
               script.locals.pair = [body, otherBody];
@@ -87,8 +85,8 @@ export default class Collider extends Component {
               ecs.addDestructionDependency(otherEntity.id, promise);
               ecs.addDestructionDependency(thisEntity.id, promise);
             }
-            if (other.$$collisionStart) {
-              const script = other.$$collisionStart.clone();
+            if (other.collisionStartScript) {
+              const script = other.collisionStartScript.clone();
               script.locals.entity = otherEntity;
               script.locals.other = thisEntity;
               script.locals.pair = [otherBody, body];
@@ -162,8 +160,8 @@ export default class Collider extends Component {
             intersection.entity.bodies[intersection.i],
             intersection.other.bodies[intersection.j],
           ];
-          if (this.$$collisionEnd) {
-            const script = this.$$collisionEnd.clone();
+          if (this.collisionEndScript) {
+            const script = this.collisionEndScript.clone();
             script.locals.other = otherEntity;
             script.locals.pair = [body, otherBody];
             const ticker = script.ticker();
@@ -171,8 +169,8 @@ export default class Collider extends Component {
             ecs.addDestructionDependency(thisEntity.id, promise);
             ecs.addDestructionDependency(otherEntity.id, promise);
           }
-          if (other.$$collisionEnd) {
-            const script = other.$$collisionEnd.clone();
+          if (other.collisionEndScript) {
+            const script = other.collisionEndScript.clone();
             script.locals.other = thisEntity;
             script.locals.pair = [otherBody, body];
             const ticker = script.ticker();
@@ -268,26 +266,6 @@ export default class Collider extends Component {
       };
     }
     instance.updateAabbs();
-    // heavy handed...
-    if ('undefined' !== typeof window) {
-      return;
-    }
-    if (instance.collisionEndScript) {
-      instance.$$collisionEnd = this.ecs.readScript(
-        instance.collisionEndScript,
-        {
-          ecs: this.ecs,
-        },
-      );
-    }
-    if (instance.collisionStartScript) {
-      instance.$$collisionStart = this.ecs.readScript(
-        instance.collisionStartScript,
-        {
-          ecs: this.ecs,
-        },
-      );
-    }
   }
   static properties = {
     bodies: {
@@ -311,8 +289,8 @@ export default class Collider extends Component {
         },
       },
     },
-    collisionEndScript: {type: 'string'},
-    collisionStartScript: {type: 'string'},
+    collisionEndScript: {type: 'script'},
+    collisionStartScript: {type: 'script'},
     isColliding: {defaultValue: 1, type: 'uint8'},
   };
 }
diff --git a/app/ecs/components/harmful.js b/app/ecs/components/harmful.js
index 9dec10c..3db78ba 100644
--- a/app/ecs/components/harmful.js
+++ b/app/ecs/components/harmful.js
@@ -6,26 +6,14 @@ export default class Harmful extends Component {
     return class HarmfulInstance extends super.instanceFromSchema() {
       harm(other) {
         const entity = ecs.get(this.entity);
-        const script = this.$$harm.clone();
+        const script = this.harmScript.clone();
         script.locals.other = other;
         script.locals.entity = entity;
         entity.Ticking.add(script.ticker());
       }
     }
   }
-  load(instance) {
-    // heavy handed...
-    if ('undefined' !== typeof window) {
-      return;
-    }
-    instance.$$harm = this.ecs.readScript(
-      instance.harmScript,
-      {
-        ecs: this.ecs,
-      },
-    );
-  }
   static properties = {
-    harmScript: {type: 'string'},
+    harmScript: {type: 'script'},
   };
 }
diff --git a/app/ecs/components/interactive.js b/app/ecs/components/interactive.js
index ecc5528..487f607 100644
--- a/app/ecs/components/interactive.js
+++ b/app/ecs/components/interactive.js
@@ -4,9 +4,8 @@ export default class Interactive extends Component {
   instanceFromSchema() {
     const {ecs} = this;
     return class ControlledInstance extends super.instanceFromSchema() {
-      $$interact;
       interact(initiator) {
-        const script = this.$$interact.clone();
+        const script = this.interactScript.clone();
         script.locals.initiator = initiator;
         script.locals.subject = ecs.get(this.entity);
         const {Ticking} = script.locals.subject;
@@ -20,20 +19,8 @@ export default class Interactive extends Component {
       }
     }
   }
-  load(instance) {
-    // heavy handed...
-    if ('undefined' !== typeof window) {
-      return;
-    }
-    instance.$$interact = this.ecs.readScript(
-      instance.interactScript,
-      {
-        ecs: this.ecs,
-      },
-    );
-  }
   static properties = {
     interacting: {type: 'uint8'},
-    interactScript: {type: 'string'},
+    interactScript: {type: 'script'},
   };
 }
diff --git a/app/ecs/components/plant.js b/app/ecs/components/plant.js
index f19aa98..ba188b8 100644
--- a/app/ecs/components/plant.js
+++ b/app/ecs/components/plant.js
@@ -5,44 +5,26 @@ export default class Plant extends Component {
     const {ecs} = this;
     const Instance = super.instanceFromSchema();
     return class PlantInstance extends Instance {
-      $$grow;
-      $$mayGrow;
       grow() {
         const {Ticking} = ecs.get(this.entity);
-        Ticking.add(this.$$grow.ticker());
+        Ticking.add(this.growScript.ticker());
       }
       mayGrow() {
-        return this.$$mayGrow.evaluate();
+        return this.mayGrowScript.evaluate();
       }
     };
   }
   load(instance) {
-    // heavy handed...
-    if ('undefined' !== typeof window) {
-      return;
-    }
-    instance.$$grow = this.ecs.readScript(
-      instance.growScript,
-      {
-        ecs: this.ecs,
-        plant: instance,
-      },
-    );
-    instance.$$mayGrow = this.ecs.readScript(
-      instance.mayGrowScript,
-      {
-        ecs: this.ecs,
-        plant: instance,
-      },
-    );
+    instance.growScript.locals.plant = instance;
+    instance.mayGrowScript.locals.plant = instance;
   }
   // heavy handed...
   markChange() {}
   static properties = {
-    growScript: {type: 'string'},
+    growScript: {type: 'script'},
     growth: {type: 'uint16'},
     growthFactor: {defaultValue: 127, type: 'uint8'},
-    mayGrowScript: {type: 'string'},
+    mayGrowScript: {type: 'script'},
     stage: {type: 'uint8'},
     stages: {
       type: 'array',
diff --git a/app/ecs/schema-types/script.js b/app/ecs/schema-types/script.js
new file mode 100644
index 0000000..9429f52
--- /dev/null
+++ b/app/ecs/schema-types/script.js
@@ -0,0 +1,22 @@
+import string from './string.js';
+
+export default function () {
+  const spec = string();
+  return {
+    ...spec,
+    json: (value) => {
+      return value ? value.path : '';
+    },
+    set: (Component, receiver, key, value) => {
+      if (!value) {
+        return;
+      }
+      receiver[key] = Component.ecs.readScript(
+        value,
+        {
+          ecs: Component.ecs,
+        },
+      );
+    },
+  };
+}
diff --git a/app/util/script.js b/app/util/script.js
index c142840..858505c 100644
--- a/app/util/script.js
+++ b/app/util/script.js
@@ -4,18 +4,19 @@ export default class Script {
 
   static registered = {};
 
-  constructor(fn, locals) {
+  constructor(path, fn, locals) {
     if (!fn) {
       throw new TypeError('Script needs a function');
     }
     this.fn = fn;
     this.iterator = null;
     this.locals = locals;
+    this.path = path;
     this.$$ticker = null;
   }
 
   clone() {
-    return new this.constructor(this.fn, this.locals);
+    return new this.constructor(this.path, this.fn, this.locals);
   }
 
   evaluate() {
@@ -27,7 +28,7 @@ export default class Script {
     if (!fn) {
       throw new Error(`no such script: ${path}`);
     }
-    const script = new this(fn, locals);
+    const script = new this(path, fn, locals);
     if (import.meta.hot) {
       const hotRef = new WeakRef(script);
       import.meta.hot.accept('./scripts.js', ({default: scripts}) => {