[#536] Fix ex.Utils.clamp min/max handling

CHANGELOG.md

@@ -9,6 +9,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 ### Added
 
 ### Changed
+- Changed Util.clamp to use math libraries. 
 
 ### Deprecated
 

src/engine/Util/Util.ts

@@ -103,8 +103,8 @@ module ex.Util {
       return outputStr;
    }
 
-   export function clamp(val, min, max) {
-      return val <= min ? min : (val >= max ? max : val);
+   export function clamp(val: number, min: number, max: number) {
+      return Math.min(Math.max(min, val), max);
    }
 
    export function randomInRange(min: number, max: number) : number {

src/spec/UtilSpec.ts

@@ -16,4 +16,15 @@ describe('Utility functions', () => {
       expect(ex.Util.getSideFromVector(ex.Vector.Up)).toBe(ex.Side.Top);
       expect(ex.Util.getSideFromVector(ex.Vector.Down)).toBe(ex.Side.Bottom);
    });
+
+   it('can clamp a number to a maximum and minimum', () => {
+      expect(ex.Util.clamp(0, 10, 20)).toBe(10);
+      expect(ex.Util.clamp(15, 10, 20)).toBe(15);
+      expect(ex.Util.clamp(30, 10, 20)).toBe(20);
+      expect(ex.Util.clamp(-Infinity, 0, 1)).toBe(0);
+      expect(ex.Util.clamp(Infinity, 0, 1)).toBe(1);
+      expect(ex.Util.clamp(12, -Infinity, Infinity)).toBe(12);
+      expect(ex.Util.clamp(12, -Infinity, 100)).toBe(12);
+      expect(ex.Util.clamp(12, -100, Infinity)).toBe(12);
+   });
 });