Improve vector by uniformizing the interface

lib/matrix.js

@@ -15,7 +15,7 @@ var Matrix = function Matrix (rows, cols, isIdentity) {
       this.m[r][c] = 0;
     }
   }
-  
+
   this.isVector = false;
 
   this.size = {rows: this.rows, cols: this.cols};
@@ -46,14 +46,14 @@ Matrix.prototype = {
   },
 
   dot: function (B) {
-    if (B.isVector ? B.v.length !== this.cols : B.rows !== this.cols) {
+    if (B.isVector ? B.v.length < this.cols : B.rows !== this.cols) {
       return new Error('number of cols of A must equal number of rows of B');
     }
 
     var C;
     if (B.isVector) {
       var arr = Array(B.v.length);
-      for (var i = 0; i < B.v.length; ++i) {
+      for (var i = 0; i < this.rows; ++i) {
         arr[i] = 0;
         for (var j = 0; j < this.rows; ++j) {
           arr[i] += parseFloat((this.get(i,j) * B.v[j]).toFixed(6));

lib/vector.js

@@ -3,19 +3,28 @@
 // -----------------------------------------------------------
 var Vector = function Vector (x, y, z) {
   if (typeof y === 'undefined' && typeof z === 'undefined') {
-    this.x = typeof x.x !== 'undefined' ? x.x : x[0];
-    this.y = typeof x.y !== 'undefined' ? x.y : x[1];
-    this.z = typeof x.z !== 'undefined' ? x.z : x[2];
+    if (typeof x.x != 'undefined') {
+      this.x = x.x;
+      this.y = x.y;
+      this.z = definedValueOrZero(x.z);
+    } else {
+      this.x = x[0];
+      this.y = x[1];
+      this.z = definedValueOrZero(x[2]);
+    }
   } else {
     this.x = x;
     this.y = y;
-    this.z = z;
+    this.z = definedValueOrZero(z);
   }
 
-  this.v = typeof this.z !== 'undefined' ? [this.x, this.y, this.z] : [this.x, this.y];
-
+  this.v = [this.x, this.y, this.z];
 };
 
+var definedValueOrZero = function(value) {
+    return typeof value !== 'undefined' ? value : 0;
+}
+
 Vector.prototype = {
   add: function (b) {
     return new Vector(this.x + b.x, this.y + b.y, this.z + b.z);
@@ -28,9 +37,10 @@ Vector.prototype = {
   isVector: true,
 
   moveTo: function(pt) {
-    this.x = typeof pt.x !== 'undefined' ? pt.x : pt[0];
-    this.y = typeof pt.y !== 'undefined' ? pt.y : pt[1];
-    this.z = typeof pt.z !== 'undefined' ? pt.z : pt[2];
+    var v = new Vector(pt);
+    this.x = v.x;
+    this.y = v.y;
+    this.z = v.z;
   },
   // cross: function (b) {
   //   var i = y * b.z - z * b.y;
@@ -43,22 +53,19 @@ Vector.prototype = {
   // },
 
   distanceFrom: function (b) {
-    var sumOfSquares = 0;
-    for (var i = 0; i < this.v.length; ++i) {
-      sumOfSquares += (this.v[i] - b.v[i]) * (this.v[i] - b.v[i]);
-    }
-
-    return Math.sqrt(sumOfSquares);
-
+    return length([this.x - b.x, this.y - b.y, this.z - b.z]);
   },
 
   length: function () {
-    var sumOfSquares = 0;
-    for (var i = 0; i < this.v.length; ++i) {
-      sumOfSquares += this.v[i] * this.v[i];
-    }
-    return Math.sqrt(sumOfSquares)
+    return length(this.v);
   }
 };
 
+var length = function length(elements) {
+  var sumOfSquares = 0;
+  for (var index = 0; index < elements.length; index++) {
+    sumOfSquares += elements[index] * elements[index]
+  }
+  return Math.sqrt(sumOfSquares);
+}
 exports = module.exports = Vector;

tests/matrix-test.js

@@ -47,7 +47,7 @@ describe('Creating matrices: ', function () {
     it('should multiply a vector by a matrix', function (done) {
       var v = new Vector(2,3);
       var C = A.dot(v);
-      C.v.should.eql([8,18]);
+      C.v.should.eql([8,18,0]);
       done();
     });
 
@@ -139,4 +139,4 @@ describe('Creating matrices: ', function () {
       done();
     });
   });
-});
+});

tests/vector-test.js

@@ -11,22 +11,22 @@ describe('Creating vectors: ', function () {
 
   it('Should pass with 2 arguments', function (done) {
     var a = new v(1,0);
-    a.v.length.should.eql(2);
-    a.v.should.eql([1,0]);
+    a.v.length.should.eql(3);
+    a.v.should.eql([1,0,0]);
     done();
   });
 
   it('should pass with 1 argument as an object', function (done) {
     var a = new v({x: 1, y: 0});
-    a.v.length.should.eql(2);
-    a.v.should.eql([1,0]);
+    a.v.length.should.eql(3);
+    a.v.should.eql([1,0,0]);
     done();
   });
 
   it('should pass with 1 argument as a vector', function (done) {
     var a = new v([1,0]);
-    a.v.length.should.eql(2);
-    a.v.should.eql([1,0]);
+    a.v.length.should.eql(3);
+    a.v.should.eql([1,0,0]);
     done();
   });
 });
@@ -67,4 +67,4 @@ describe('Between two vectors: ', function () {
     lenB.should.eql(Math.sqrt(2));
     done();
   })
-});
+});