Merge pull request jriecken#53 from jriecken/fix-scaling-by-zero

Check explicitly for undefined y param when scaling. Fixes jriecken#52
Wilkor · May 24, 2018 · 92b4ac2 · 92b4ac2
2 parents 217f5c0 + ac7f329
commit 92b4ac2
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diff --git a/SAT.js b/SAT.js
@@ -159,7 +159,7 @@
    */
   Vector.prototype['scale'] = Vector.prototype.scale = function(x,y) {
     this['x'] *= x;
-    this['y'] *= y || x;
+    this['y'] *= typeof y != 'undefined' ? y : x;
     return this;
   };
 

diff --git a/test/test.js b/test/test.js
@@ -1,6 +1,24 @@
 var SAT = require('..');
 var assert = require('assert');
 
+describe('Vector.scale', function() {
+  it('should scale by zero properly', function() {
+    var V = SAT.Vector;
+    var v1 = new V(5, 5);
+    v1.scale(10, 10);
+    assert(v1.x === 50);
+    assert(v1.y === 50);
+
+    v1.scale(0, 1);
+    assert(v1.x === 0);
+    assert(v1.y === 50);
+
+    v1.scale(1, 0);
+    assert(v1.x === 0);
+    assert(v1.y === 0);
+  });
+});
+
 describe("Polygon.getCentroid", function() {
   it("should calculate the correct value for a square", function() {
     var V = SAT.Vector;