diff --git a/js/common/model/LaserViewEnum.ts b/js/common/model/LaserViewEnum.ts
index 2368d79c..be10fcbe 100644
--- a/js/common/model/LaserViewEnum.ts
+++ b/js/common/model/LaserViewEnum.ts
@@ -1,3 +1,3 @@
 // Copyright 2021, University of Colorado Boulder
-type ColorModeEnum = 'ray' | 'wave';
-export default ColorModeEnum;
\ No newline at end of file
+type LaserViewEnum = 'ray' | 'wave';
+export default LaserViewEnum;
\ No newline at end of file
diff --git a/js/common/model/RayTypeEnum.ts b/js/common/model/RayTypeEnum.ts
new file mode 100644
index 00000000..f53fb3fc
--- /dev/null
+++ b/js/common/model/RayTypeEnum.ts
@@ -0,0 +1,3 @@
+// Copyright 2021, University of Colorado Boulder
+type RayTypeEnum = 'incident' | 'reflected' | 'transmitted';
+export default RayTypeEnum;
\ No newline at end of file
diff --git a/js/intro/view/AngleNode.ts b/js/intro/view/AngleNode.ts
index 42945e70..196125a7 100644
--- a/js/intro/view/AngleNode.ts
+++ b/js/intro/view/AngleNode.ts
@@ -19,6 +19,7 @@ import Text from '../../../../scenery/js/nodes/Text.js';
 import Panel from '../../../../sun/js/Panel.js';
 import bendingLight from '../../bendingLight.js';
 import LightRay from '../../common/model/LightRay.js';
+import RayTypeEnum from '../../common/model/RayTypeEnum.js';
 
 // constants
 const CIRCLE_RADIUS = 50; // radius of the circular arc in stage coordinates
@@ -150,7 +151,7 @@ class AngleNode extends Node {
      * @param type
      * @returns {LightRay}
      */
-    const getRay = ( type: 'incident' | 'reflected' | 'transmitted' | null ) => { // TODO: enum
+    const getRay = ( type: RayTypeEnum | null ) => {
       let selected = null;
       for ( let i = 0; i < rays.length; i++ ) {
         const ray = rays[ i ];