diff --git a/config-serializer/TypeChecker.ts b/config-serializer/TypeChecker.ts
new file mode 100644
index 00000000..4f2c9210
--- /dev/null
+++ b/config-serializer/TypeChecker.ts
@@ -0,0 +1,13 @@
+class TypeChecker {
+
+    static firstValidScancode = 1;
+    static lastValidScancode = 231;
+
+    static isUInt8Valid(uint8: number): boolean {
+        return 0 <= uint8 && uint8 <= 255;
+    }
+
+    static isScancodeValid(scancode: number): boolean {
+        return TypeChecker.firstValidScancode <= scancode && scancode <= TypeChecker.lastValidScancode;
+    }
+}
diff --git a/config-serializer/UhkBuffer.ts b/config-serializer/UhkBuffer.ts
index f1c812d3..5c3889fe 100644
--- a/config-serializer/UhkBuffer.ts
+++ b/config-serializer/UhkBuffer.ts
@@ -1,4 +1,3 @@
-
 class UhkBuffer {
     private static eepromSize = 32 * 1024;
     private static maxStringByteLength = 0xFFFF;
diff --git a/config-serializer/config-items/KeyAction.ts b/config-serializer/config-items/KeyAction.ts
index af916a27..26c06c57 100644
--- a/config-serializer/config-items/KeyAction.ts
+++ b/config-serializer/config-items/KeyAction.ts
@@ -17,7 +17,7 @@ class KeyAction {
         let keyActionFirstByte = buffer.readUInt8();
         buffer.backtrack();
 
-        if (KeystrokeAction.isScancodeValid(keyActionFirstByte)) {
+        if (TypeChecker.isScancodeValid(keyActionFirstByte)) {
             return new KeystrokeAction().fromBinary(buffer);
         } else if (keyActionFirstByte === MouseAction.keyActionId) {
             return new MouseAction().fromBinary(buffer);
diff --git a/config-serializer/config-items/KeystrokeAction.ts b/config-serializer/config-items/KeystrokeAction.ts
index 3d3fd201..76105600 100644
--- a/config-serializer/config-items/KeystrokeAction.ts
+++ b/config-serializer/config-items/KeystrokeAction.ts
@@ -1,8 +1,6 @@
 class KeystrokeAction extends KeyAction implements Serializable<KeystrokeAction> {
 
     static keyActionTypeString = 'keystroke';
-    static firstValidScancode = 1;
-    static lastValidScancode = 231;
 
     modifierMask: number;
 
@@ -13,17 +11,12 @@ class KeystrokeAction extends KeyAction implements Serializable<KeystrokeAction>
     }
 
     set scancode(value) {
-        if (!KeystrokeAction.isScancodeValid(value)) {
+        if (!TypeChecker.isScancodeValid(value)) {
             throw 'Invalid KeystrokeAction.scancode: ${scancode}';
         }
         this._scancode = value;
     }
 
-    static isScancodeValid(scancode) {
-        return KeystrokeAction.firstValidScancode <= scancode &&
-               scancode <= KeystrokeAction.lastValidScancode;
-    }
-
     fromJsObject(jsObject: any): KeystrokeAction {
         this.scancode = jsObject.scancode;
         this.modifierMask = jsObject.modifierMask;
diff --git a/config-serializer/config-items/PlayMacroAction.ts b/config-serializer/config-items/PlayMacroAction.ts
index 0b757de9..9c63c4ae 100644
--- a/config-serializer/config-items/PlayMacroAction.ts
+++ b/config-serializer/config-items/PlayMacroAction.ts
@@ -10,16 +10,12 @@ class PlayMacroAction extends KeyAction implements Serializable<PlayMacroAction>
     }
 
     set macroId(value) {
-        if (!PlayMacroAction.isMacroIdValid(value)) {
+        if (!TypeChecker.isUInt8Valid(value)) {
             throw 'Invalid PlayMacroAction.macroId: ${value}';
         }
         this._macroId = value;
     }
 
-    static isMacroIdValid(macroId) {
-        return 0 <= macroId && macroId <= 255;
-    }
-
     fromJsObject(jsObject: any): PlayMacroAction {
         this.macroId = jsObject.macroId;
         return this;
diff --git a/config-serializer/config-items/SwitchKeymapAction.ts b/config-serializer/config-items/SwitchKeymapAction.ts
index f5c24783..dcc28d63 100644
--- a/config-serializer/config-items/SwitchKeymapAction.ts
+++ b/config-serializer/config-items/SwitchKeymapAction.ts
@@ -10,16 +10,12 @@ class SwitchKeymapAction extends KeyAction implements Serializable<SwitchKeymapA
     }
 
     set keymapId(value) {
-        if (!SwitchKeymapAction.isKeymapIdValid(value)) {
+        if (!TypeChecker.isUInt8Valid(value)) {
             throw 'Invalid SwitchKeymapAction.keymapId: ${value}';
         }
         this._keymapId = value;
     }
 
-    static isKeymapIdValid(keymapId) {
-        return 0 <= keymapId && keymapId <= 255;
-    }
-
     fromJsObject(jsObject: any): SwitchKeymapAction {
         this.keymapId = jsObject.keymapId;
         return this;
diff --git a/config-serializer/serializeConfig.ts b/config-serializer/serializeConfig.ts
index a75258a7..563e6d06 100644
--- a/config-serializer/serializeConfig.ts
+++ b/config-serializer/serializeConfig.ts
@@ -1,3 +1,4 @@
+/// <reference path="TypeChecker.ts" />
 /// <reference path="Serializable.ts" />
 /// <reference path="UhkBuffer.ts" />
 /// <reference path="config-items/config-items.ts" />