diff --git a/app/ecs/component.js b/app/ecs/component.js
index 96275ca..bac1f87 100644
--- a/app/ecs/component.js
+++ b/app/ecs/component.js
@@ -38,7 +38,8 @@ export default class Component {
       return [];
     }
     const allocated = this.allocateMany(entries.length);
-    const {properties} = this.constructor.schema.specification;
+    const {properties} = this.constructor.schema.specification.concrete;
+    const Schema = this.constructor.schema.constructor;
     const keys = Object.keys(properties);
     const promises = [];
     for (let i = 0; i < entries.length; ++i) {
@@ -47,13 +48,15 @@ export default class Component {
       this.data[allocated[i]].entity = entityId;
       for (let k = 0; k < keys.length; ++k) {
         const j = keys[k];
-        const {defaultValue} = properties[j];
         const instance = this.data[allocated[i]];
         if (j in values) {
           instance[j] = values[j];
         }
-        else if ('undefined' !== typeof defaultValue) {
-          instance[j] = defaultValue;
+        else {
+          const defaultValue = Schema.defaultValue(properties[j]);
+          if ('undefined' !== typeof defaultValue) {
+            instance[j] = defaultValue;
+          }
         }
       }
       promises.push(this.load(this.data[allocated[i]]));
@@ -67,7 +70,7 @@ export default class Component {
   }
 
   deserialize(entityId, view, offset) {
-    const {properties} = this.constructor.schema.specification;
+    const {properties} = this.constructor.schema.specification.concrete;
     const instance = this.get(entityId);
     const deserialized = this.constructor.schema.deserialize(view, offset);
     for (const key in properties) {
@@ -96,11 +99,11 @@ export default class Component {
   }
 
   static filterDefaults(instance) {
-    const {properties} = this.schema.specification;
+    const {properties} = this.schema.specification.concrete;
+    const Schema = this.schema.constructor;
     const json = {};
     for (const key in properties) {
-      const {defaultValue} = properties[key];
-      if (key in instance && instance[key] !== defaultValue) {
+      if (key in instance && instance[key] !== Schema.defaultValue(properties[key])) {
         json[key] = instance[key];
       }
     }
@@ -136,16 +139,16 @@ export default class Component {
 
   instanceFromSchema() {
     const Component = this;
-    const {specification} = Component.constructor.schema;
+    const {concrete} = Component.constructor.schema.specification;
+    const Schema = Component.constructor.schema.constructor;
     const Instance = class {
       $$entity = 0;
       constructor() {
         this.$$reset();
       }
       $$reset() {
-        for (const key in specification.properties) {
-          const {defaultValue} = specification.properties[key];
-          this[`$$${key}`] = defaultValue;
+        for (const key in concrete.properties) {
+          this[`$$${key}`] = Schema.defaultValue(concrete.properties[key]);
         }
       }
       destroy() {}
@@ -166,7 +169,7 @@ export default class Component {
         this.$$reset();
       },
     };
-    for (const key in specification.properties) {
+    for (const key in concrete.properties) {
       properties[key] = {
         get: function get() {
           return this[`$$${key}`];
diff --git a/app/ecs/schema-types/array.js b/app/ecs/schema-types/array.js
new file mode 100644
index 0000000..3f5dec6
--- /dev/null
+++ b/app/ecs/schema-types/array.js
@@ -0,0 +1,40 @@
+export default function (Schema) {
+  return {
+    defaultValue: () => [],
+    deserialize: (view, offset, {subtype}) => {
+      const length = view.getUint32(offset.value, true);
+      offset.value += 4;
+      const value = [];
+      for (let i = 0; i < length; ++i) {
+        value.push(Schema.deserialize(view, offset, subtype));
+      }
+      return value;
+    },
+    normalize: ({subtype}) => {
+      return {
+        subtype: Schema.normalize(subtype),
+      }
+    },
+    serialize: (source, view, offset, {subtype}) => {
+      view.setUint32(offset, source.length, true);
+      let size = 4;
+      for (const element of source) {
+        size += Schema.serialize(
+          element,
+          view,
+          offset + size,
+          subtype,
+        );
+      }
+      return size;
+    },
+    sizeOf: (instance, {subtype}) => {
+      let size = 4;
+      for (const element of instance) {
+        size += Schema.sizeOf(element, subtype);
+      }
+      return size;
+    },
+    staticSizeOf: () => 0,
+  };
+}
diff --git a/app/ecs/schema-types/float32.js b/app/ecs/schema-types/float32.js
new file mode 100644
index 0000000..c5d4fa9
--- /dev/null
+++ b/app/ecs/schema-types/float32.js
@@ -0,0 +1,16 @@
+export default function () {
+  return {
+    defaultValue: () => 0,
+    deserialize: (view, offset) => {
+      const value = view.getFloat32(offset.value, true);
+      offset.value += 4;
+      return value;
+    },
+    serialize: (source, view, offset) => {
+      view.setFloat32(offset, source, true);
+      return 4;
+    },
+    sizeOf: () => 4,
+    staticSizeOf: () => 4,
+  };
+}
diff --git a/app/ecs/schema-types/float64.js b/app/ecs/schema-types/float64.js
new file mode 100644
index 0000000..a54d7b8
--- /dev/null
+++ b/app/ecs/schema-types/float64.js
@@ -0,0 +1,16 @@
+export default function () {
+  return {
+    defaultValue: () => 0,
+    deserialize: (view, offset) => {
+      const value = view.getFloat64(offset.value, true);
+      offset.value += 8;
+      return value;
+    },
+    serialize: (source, view, offset) => {
+      view.setFloat64(offset, source, true);
+      return 8;
+    },
+    sizeOf: () => 8,
+    staticSizeOf: () => 8,
+  };
+}
diff --git a/app/ecs/schema-types/int16.js b/app/ecs/schema-types/int16.js
new file mode 100644
index 0000000..e025f56
--- /dev/null
+++ b/app/ecs/schema-types/int16.js
@@ -0,0 +1,16 @@
+export default function () {
+  return {
+    defaultValue: () => 0,
+    deserialize: (view, offset) => {
+      const value = view.getInt16(offset.value, true);
+      offset.value += 2;
+      return value;
+    },
+    serialize: (source, view, offset) => {
+      view.setInt16(offset, source, true);
+      return 2;
+    },
+    sizeOf: () => 2,
+    staticSizeOf: () => 2,
+  };
+}
diff --git a/app/ecs/schema-types/int32.js b/app/ecs/schema-types/int32.js
new file mode 100644
index 0000000..bcfae50
--- /dev/null
+++ b/app/ecs/schema-types/int32.js
@@ -0,0 +1,16 @@
+export default function () {
+  return {
+    defaultValue: () => 0,
+    deserialize: (view, offset) => {
+      const value = view.getInt32(offset.value, true);
+      offset.value += 4;
+      return value;
+    },
+    serialize: (source, view, offset) => {
+      view.setInt32(offset, source, true);
+      return 4;
+    },
+    sizeOf: () => 4,
+    staticSizeOf: () => 4,
+  };
+}
diff --git a/app/ecs/schema-types/int64.js b/app/ecs/schema-types/int64.js
new file mode 100644
index 0000000..b380ad0
--- /dev/null
+++ b/app/ecs/schema-types/int64.js
@@ -0,0 +1,16 @@
+export default function () {
+  return {
+    defaultValue: () => 0n,
+    deserialize: (view, offset) => {
+      const value = view.getBigInt64(offset.value, true);
+      offset.value += 8;
+      return value;
+    },
+    serialize: (source, view, offset) => {
+      view.setBigInt64(offset, source, true);
+      return 8;
+    },
+    sizeOf: () => 8,
+    staticSizeOf: () => 8,
+  };
+}
diff --git a/app/ecs/schema-types/int8.js b/app/ecs/schema-types/int8.js
new file mode 100644
index 0000000..786c9d1
--- /dev/null
+++ b/app/ecs/schema-types/int8.js
@@ -0,0 +1,16 @@
+export default function () {
+  return {
+    defaultValue: () => 0,
+    deserialize: (view, offset) => {
+      const value = view.getInt8(offset.value, true);
+      offset.value += 1;
+      return value;
+    },
+    serialize: (source, view, offset) => {
+      view.setInt8(offset, source, true);
+      return 1;
+    },
+    sizeOf: () => 1,
+    staticSizeOf: () => 1,
+  };
+}
diff --git a/app/ecs/schema-types/map.js b/app/ecs/schema-types/map.js
new file mode 100644
index 0000000..71be98e
--- /dev/null
+++ b/app/ecs/schema-types/map.js
@@ -0,0 +1,50 @@
+export default function (Schema) {
+  return {
+    defaultValue: () => ({}),
+    deserialize: (view, offset, concrete) => {
+      const length = view.getUint32(offset.value, true);
+      offset.value += 4;
+      const value = {};
+      for (let i = 0; i < length; ++i) {
+        const key = Schema.deserialize(view, offset, concrete.key);
+        value[key] = Schema.deserialize(view, offset, concrete.value);
+      }
+      return value;
+    },
+    normalize: ({value}) => {
+      return {
+        key: Schema.normalize({type: 'string'}),
+        value: Schema.normalize(value),
+      }
+    },
+    serialize: (source, view, offset, concrete) => {
+      const keys = Object.keys(source);
+      view.setUint32(offset, keys.length, true);
+      let size = 4;
+      for (const key of keys) {
+        size += Schema.serialize(
+          key,
+          view,
+          offset + size,
+          concrete.key,
+        );
+        size += Schema.serialize(
+          source[key],
+          view,
+          offset + size,
+          concrete.value,
+        );
+      }
+      return size;
+    },
+    sizeOf: (instance, concrete) => {
+      let size = 4;
+      for (const key in instance) {
+        size += Schema.sizeOf(key, concrete.key);
+        size += Schema.sizeOf(instance[key], concrete.value);
+      }
+      return size;
+    },
+    staticSizeOf: () => 0,
+  };
+}
diff --git a/app/ecs/schema-types/object.js b/app/ecs/schema-types/object.js
new file mode 100644
index 0000000..8c37b84
--- /dev/null
+++ b/app/ecs/schema-types/object.js
@@ -0,0 +1,55 @@
+export default function (Schema) {
+  return {
+    defaultValue: ({properties}) => {
+      const object = {};
+      for (const key in properties) {
+        object[key] = Schema.defaultValue(properties[key]);
+      }
+      return object;
+    },
+    deserialize: (view, offset, {properties}) => {
+      const value = {};
+      for (const key in properties) {
+        value[key] = Schema.deserialize(view, offset, properties[key]);
+      }
+      return value;
+    },
+    normalize: ({properties}) => {
+      const normalized = {properties: {}};
+      for (const key in properties) {
+        normalized.properties[key] = Schema.normalize(properties[key])
+      }
+      return normalized;
+    },
+    serialize: (source, view, offset, {properties}) => {
+      let size = 0;
+      for (const key in properties) {
+        size += Schema.serialize(
+          source[key],
+          view,
+          offset + size,
+          properties[key],
+        );
+      }
+      return size;
+    },
+    sizeOf: (instance, {properties}) => {
+      let size = 0;
+      for (const key in properties) {
+        size += Schema.sizeOf(instance[key], properties[key]);
+      }
+      return size;
+    },
+    staticSizeOf: ({properties}) => {
+      let size = 0;
+      for (const key in properties) {
+        const propertySize = Schema.size(properties[key]);
+        if (0 === propertySize) {
+          return 0;
+        }
+        size += propertySize;
+      }
+      return size;
+    },
+  };
+}
diff --git a/app/ecs/schema-types/string.js b/app/ecs/schema-types/string.js
new file mode 100644
index 0000000..e05624c
--- /dev/null
+++ b/app/ecs/schema-types/string.js
@@ -0,0 +1,31 @@
+const decoder = new TextDecoder();
+const encoder = new TextEncoder();
+
+export default function () {
+  return {
+    defaultValue: () => '',
+    deserialize: (view, offset) => {
+      const length = view.getUint32(offset.value, true);
+      offset.value += 4;
+      const {buffer, byteOffset} = view;
+      const value = decoder.decode(new DataView(buffer, byteOffset + offset.value, length));
+      offset.value += length;
+      return value;
+    },
+    serialize: (source, view, offset) => {
+      const bytes = encoder.encode(source);
+      view.setUint32(offset, bytes.length, true);
+      offset += 4;
+      for (let i = 0; i < bytes.length; ++i) {
+        view.setUint8(offset++, bytes[i]);
+      }
+      return 4 + bytes.length;
+    },
+    sizeOf: (instance) => {
+      let size = 4;
+      size += (encoder.encode(instance)).length;
+      return size;
+    },
+    staticSizeOf: () => 0,
+  };
+}
diff --git a/app/ecs/schema-types/uint16.js b/app/ecs/schema-types/uint16.js
new file mode 100644
index 0000000..f7c59ba
--- /dev/null
+++ b/app/ecs/schema-types/uint16.js
@@ -0,0 +1,16 @@
+export default function () {
+  return {
+    defaultValue: () => 0,
+    deserialize: (view, offset) => {
+      const value = view.getUint16(offset.value, true);
+      offset.value += 2;
+      return value;
+    },
+    serialize: (source, view, offset) => {
+      view.setUint16(offset, source, true);
+      return 2;
+    },
+    sizeOf: () => 2,
+    staticSizeOf: () => 2,
+  };
+}
diff --git a/app/ecs/schema-types/uint32.js b/app/ecs/schema-types/uint32.js
new file mode 100644
index 0000000..bfb563f
--- /dev/null
+++ b/app/ecs/schema-types/uint32.js
@@ -0,0 +1,16 @@
+export default function () {
+  return {
+    defaultValue: () => 0,
+    deserialize: (view, offset) => {
+      const value = view.getUint32(offset.value, true);
+      offset.value += 4;
+      return value;
+    },
+    serialize: (source, view, offset) => {
+      view.setUint32(offset, source, true);
+      return 4;
+    },
+    sizeOf: () => 4,
+    staticSizeOf: () => 4,
+  };
+}
diff --git a/app/ecs/schema-types/uint64.js b/app/ecs/schema-types/uint64.js
new file mode 100644
index 0000000..864f463
--- /dev/null
+++ b/app/ecs/schema-types/uint64.js
@@ -0,0 +1,16 @@
+export default function () {
+  return {
+    defaultValue: () => 0n,
+    deserialize: (view, offset) => {
+      const value = view.getBigUint64(offset.value, true);
+      offset.value += 8;
+      return value;
+    },
+    serialize: (source, view, offset) => {
+      view.setBigUint64(offset, source, true);
+      return 8;
+    },
+    sizeOf: () => 8,
+    staticSizeOf: () => 8,
+  };
+}
diff --git a/app/ecs/schema-types/uint8.js b/app/ecs/schema-types/uint8.js
new file mode 100644
index 0000000..a6c84ee
--- /dev/null
+++ b/app/ecs/schema-types/uint8.js
@@ -0,0 +1,16 @@
+export default function () {
+  return {
+    defaultValue: () => 0,
+    deserialize: (view, offset) => {
+      const value = view.getUint8(offset.value, true);
+      offset.value += 1;
+      return value;
+    },
+    serialize: (source, view, offset) => {
+      view.setUint8(offset, source, true);
+      return 1;
+    },
+    sizeOf: () => 1,
+    staticSizeOf: () => 1,
+  };
+}
diff --git a/app/ecs/schema.js b/app/ecs/schema.js
index a379f65..16d1749 100644
--- a/app/ecs/schema.js
+++ b/app/ecs/schema.js
@@ -1,303 +1,66 @@
-const encoder = new TextEncoder();
-
 export default class Schema {
 
-  $$size = 0;
+  static $$types = {};
 
   specification;
 
-  static viewGetMethods = {
-    uint8: 'getUint8',
-    int8: 'getInt8',
-    uint16: 'getUint16',
-    int16: 'getInt16',
-    uint32: 'getUint32',
-    int32: 'getInt32',
-    float32: 'getFloat32',
-    float64: 'getFloat64',
-    int64: 'getBigInt64',
-    uint64: 'getBigUint64',
-  };
-
-  static viewSetMethods = {
-    uint8: 'setUint8',
-    int8: 'setInt8',
-    uint16: 'setUint16',
-    int16: 'setInt16',
-    uint32: 'setUint32',
-    int32: 'setInt32',
-    float32: 'setFloat32',
-    float64: 'setFloat64',
-    int64: 'setBigInt64',
-    uint64: 'setBigUint64',
-  };
-
   constructor(specification) {
     this.specification = this.constructor.normalize(specification);
   }
 
-  static deserialize(view, offset, specification) {
-    const viewGetMethod = this.viewGetMethods[specification.type];
-    if (viewGetMethod) {
-      const value = view[viewGetMethod](offset.value, true);
-      offset.value += this.size(specification);
-      return value;
-    }
-    switch (specification.type) {
-      case 'array': {
-        const length = view.getUint32(offset.value, true);
-        offset.value += 4;
-        const value = [];
-        for (let i = 0; i < length; ++i) {
-          value.push(this.deserialize(view, offset, specification.subtype));
-        }
-        return value;
-      }
-      case 'map': {
-        const length = view.getUint32(offset.value, true);
-        offset.value += 4;
-        const value = {};
-        for (let i = 0; i < length; ++i) {
-          const key = this.deserialize(view, offset, {type: 'string'});
-          value[key] = this.deserialize(view, offset, specification.value);
-        }
-        return value;
-      }
-      case 'object': {
-        const value = {};
-        for (const key in specification.properties) {
-          value[key] = this.deserialize(view, offset, specification.properties[key]);
-        }
-        return value;
-      }
-      case 'string': {
-        const length = view.getUint32(offset.value, true);
-        offset.value += 4;
-        const {buffer, byteOffset} = view;
-        const decoder = new TextDecoder();
-        const value = decoder.decode(new DataView(buffer, byteOffset + offset.value, length));
-        offset.value += length;
-        return value;
-      }
-    }
-  }
-
-  deserialize(view, offset = 0) {
-    const wrapped = {value: offset};
-    return this.constructor.deserialize(view, wrapped, this.specification);
-  }
-
-  static defaultValue(specification) {
-    if (specification.defaultValue) {
-      return specification.defaultValue;
-    }
-    switch (specification.type) {
-      case 'uint8': case 'int8':
-      case 'uint16': case 'int16':
-      case 'uint32': case 'int32':
-      case 'uint64': case 'int64':
-      case 'float32': case 'float64': {
-        return 0;
-      }
-      case 'array': {
-        return [];
-      }
-      case 'map': {
-        return {};
-      }
-      case 'object': {
-        const object = {};
-        for (const key in specification.properties) {
-          object[key] = this.defaultValue(specification.properties[key]);
-        }
-        return object;
-      }
-      case 'string': {
-        return '';
-      }
+  static defaultValue({$, concrete}) {
+    if (concrete.defaultValue) {
+      return concrete.defaultValue;
     }
+    return $.defaultValue(concrete);
   }
 
   defaultValue() {
     return this.constructor.defaultValue(this.specification);
   }
 
-  static normalize(specification) {
-    let normalized = specification;
-    switch (specification.type) {
-      case 'array': {
-        normalized.subtype = this.normalize(specification.subtype);
-        break;
-      }
-      case 'map': {
-        normalized.value = this.normalize(specification.value);
-        break;
-      }
-      case 'object': {
-        for (const key in specification.properties) {
-          normalized.properties[key] = this.normalize(specification.properties[key])
-        }
-        break;
-      }
-      case 'uint8':
-      case 'int8':
-      case 'uint16':
-      case 'int16':
-      case 'uint32':
-      case 'int32':
-      case 'uint64':
-      case 'int64':
-      case 'float32':
-      case 'float64':
-      case 'string': {
-        break;
-      }
-      /* v8 ignore next 2 */
-      default:
-        throw new TypeError(`invalid specification: ${JSON.stringify(specification)}`);
-    }
-    return {...normalized, defaultValue: this.defaultValue(normalized)};
+  static deserialize(view, offset, {$, concrete}) {
+    return $.deserialize(view, offset, concrete);
   }
 
-  static serialize(source, view, offset, specification) {
-    const viewSetMethod = this.viewSetMethods[specification.type];
-    if (viewSetMethod) {
-      view[viewSetMethod](offset, source, true);
-      return this.size(specification);
-    }
-    switch (specification.type) {
-      case 'array': {
-        view.setUint32(offset, source.length, true);
-        let arraySize = 4;
-        for (const element of source) {
-          arraySize += this.serialize(
-            element,
-            view,
-            offset + arraySize,
-            specification.subtype,
-          );
-        }
-        return arraySize;
-      }
-      case 'map': {
-        const keys = Object.keys(source);
-        view.setUint32(offset, keys.length, true);
-        let mapSize = 4;
-        for (const key of keys) {
-          mapSize += this.serialize(
-            key,
-            view,
-            offset + mapSize,
-            {type: 'string'},
-          );
-          mapSize += this.serialize(
-            source[key],
-            view,
-            offset + mapSize,
-            specification.value,
-          );
-        }
-        return mapSize;
-      }
-      case 'object': {
-        let objectSize = 0;
-        for (const key in specification.properties) {
-          objectSize += this.serialize(
-            source[key],
-            view,
-            offset + objectSize,
-            specification.properties[key],
-          );
-        }
-        return objectSize;
-      }
-      case 'string': {
-        const encoder = new TextEncoder();
-        const bytes = encoder.encode(source);
-        view.setUint32(offset, bytes.length, true);
-        offset += 4;
-        for (let i = 0; i < bytes.length; ++i) {
-          view.setUint8(offset++, bytes[i]);
-        }
-        return 4 + bytes.length;
-      }
+  deserialize(view, offset = 0) {
+    return this.constructor.deserialize(view, {value: offset}, this.specification);
+  }
+
+  static normalize({type, ...rest}) {
+    const $$type = this.$$types[type];
+    if (!$$type) {
+      throw new TypeError(`unregistered schema type '${type}'`);
     }
+    return {
+      $: this.$$types[type],
+      concrete: $$type.normalize ? $$type.normalize(rest) : rest,
+    };
+  }
+
+  static serialize(source, view, offset, {$, concrete}) {
+    return $.serialize(source, view, offset, concrete);
   }
 
   serialize(source, view, offset = 0) {
     this.constructor.serialize(source, view, offset, this.specification);
   }
 
-  static sizeOf(concrete, specification) {
-    const size = this.size(specification);
-    if (size > 0) {
-      return size;
-    }
-    let fullSize = 0;
-    const {type} = specification;
-    switch (type) {
-      case 'array': {
-        fullSize += 4;
-        for (const element of concrete) {
-          fullSize += this.sizeOf(element, specification.subtype);
-        }
-        break;
-      }
-      case 'map': {
-        fullSize += 4;
-        for (const key in concrete) {
-          fullSize += this.sizeOf(key, {type: 'string'});
-          fullSize += this.sizeOf(concrete[key], specification.value);
-        }
-        break;
-      }
-      case 'object': {
-        for (const key in specification.properties) {
-          fullSize += this.sizeOf(concrete[key], specification.properties[key]);
-        }
-        break;
-      }
-      case 'string':
-        fullSize += 4;
-        fullSize += (encoder.encode(concrete)).length;
-        break;
-    }
-    return fullSize;
+  static sizeOf(instance, {$, concrete}) {
+    return $.sizeOf(instance, concrete);
   }
 
-  sizeOf(concrete) {
-    return this.constructor.sizeOf(concrete, this.specification);
+  sizeOf(instance) {
+    return this.constructor.sizeOf(instance, this.specification);
   }
 
-  static size(specification) {
-    switch (specification.type) {
-      case 'array': return 0;
-      case 'map': return 0; // TODO could be fixed-size w/ fixed-size key
-      case 'object': {
-        let size = 0;
-        for (const key in specification.properties) {
-          const propertySize = this.size(specification.properties[key]);
-          if (0 === propertySize) {
-            return 0;
-          }
-          size += propertySize;
-        }
-        return size;
-      }
-      case 'uint8': case 'int8': {
-        return 1;
-      }
-      case 'uint16': case 'int16': {
-        return 2;
-      }
-      case 'uint32': case 'int32': case 'float32': {
-        return 4;
-      }
-      case 'uint64': case 'int64': case 'float64': {
-        return 8;
-      }
-      default: return 0;
-    }
+  static size({$, concrete}) {
+    return $.staticSizeOf(concrete);
   }
 
 }
+
+const imports = import.meta.glob('./schema-types/*.js', {eager: true, import: 'default'});
+for (const path in imports) {
+  Schema.$$types[path.replace(/.\/schema-types\/(.*)\.js/, '$1')] = imports[path](Schema);
+}
diff --git a/app/ecs/schema.test.js b/app/ecs/schema.test.js
index 50a1d5d..366028e 100644
--- a/app/ecs/schema.test.js
+++ b/app/ecs/schema.test.js
@@ -4,10 +4,6 @@ import Schema from './schema.js';
 
 test('defaults values', () => {
   const compare = (specification, value) => {
-    expect(Schema.defaultValue(specification))
-      .to.deep.equal(value);
-    expect(new Schema(specification).specification.defaultValue)
-      .to.deep.equal(value);
     expect(new Schema(specification).defaultValue())
       .to.deep.equal(value);
   };
@@ -18,13 +14,17 @@ test('defaults values', () => {
     'int16',
     'uint32',
     'int32',
-    'uint64',
-    'int64',
     'float32',
     'float64',
   ].forEach((type) => {
     compare({type}, 0);
   });
+  [
+    'uint64',
+    'int64',
+  ].forEach((type) => {
+    compare({type}, 0n);
+  });
   compare({type: 'string'}, '');
   compare({type: 'array', subtype: {type: 'string'}}, []);
   compare(
@@ -167,11 +167,11 @@ test('encodes and decodes', () => {
     [{type: 'object', properties: {foo: {type: 'uint8'}, bar: {type: 'string'}}}, {foo: 64, bar: 'baz'}],
     [{type: 'object', properties: {foo: {type: 'uint8'}}}, {foo: 64}],
   ];
-  entries.forEach(([specification, concrete]) => {
+  entries.forEach(([specification, instance]) => {
     const schema = new Schema(specification);
-    const view = new DataView(new ArrayBuffer(schema.sizeOf(concrete)));
-    schema.serialize(concrete, view);
-    expect(concrete)
+    const view = new DataView(new ArrayBuffer(schema.sizeOf(instance)));
+    schema.serialize(instance, view);
+    expect(instance)
       .to.deep.equal(schema.deserialize(view));
   });
 });