updated shortFmt filter to be more "forgiving" with various inputs

src/_filter/math/math.js

@@ -4,7 +4,20 @@
  * @description
  * reference to global Math object
  */
+
 angular.module('a8m.math', [])
   .factory('$math', ['$window', function ($window) {
-    return $window.Math;
+
+    var math = $window.Math;
+    math.filterFactory = function(fn){
+        return function(input){
+    	    input = Number(input);
+    	    return input != input
+    		    ? input
+    		    : fn.apply(this, arguments);
+        }
+    }
+
+    return math;
+
   }]);

src/_filter/math/short-fmt.js

@@ -8,23 +8,30 @@
  * i.e: K for one thousand, M for Million, B for billion
  * e.g: number of users:235,221, decimal:1 => 235.2 K
  */
+
 angular.module('a8m.math.shortFmt', ['a8m.math'])
-  .filter('shortFmt', ['$math', function ($math) {
-    return function (number, decimal) {
-      if(isNumber(decimal) && isFinite(decimal) && decimal%1===0 && decimal >= 0 &&
-        isNumber(number) && isFinite(number)){
-
-          if(number < 1e3) {
-              return number;
-          } else if(number < 1e6) {
-              return convertToDecimal((number / 1e3), decimal, $math) + ' K';
-          } else if(number < 1e9){
-              return convertToDecimal((number / 1e6), decimal, $math) + ' M';
-          } else {
-            return convertToDecimal((number / 1e9), decimal, $math) + ' B';
-          }
 
-	  }
-    return "NaN";
-	}
-}]);
+.filter('shortFmt', ['$math', function($math) {
+    return $math.filterFactory(function(number, decimal) {
+            if (isNumber(decimal) 
+              && isFinite(decimal) 
+              && decimal % 1 === 0 
+              && decimal >= 0 
+              && isNumber(number) 
+              && isFinite(number)) {
+                var sign = 1;
+                if(number < 0){
+                    sign = -1;
+                    number = number * sign;
+                } else if (number == 0) { return '0'; }
+                var k = 1000, sizes = ['',' K', ' M', ' B', ' T', ' Q'];
+                // i = nth exponent of k by way of the change of base formula for logs
+                // then taking the floor of that to get only the integer value of the number
+                var i = $math.floor($math.log(number) / $math.log(k));
+                return (sign * (number / $math.pow(k, i))).toFixed(decimal) + sizes[i];
+
+            } else {
+                return 'NaN';
+            }
+        })
+    }]);

test/spec/filter/math/short-fmt.js

@@ -11,28 +11,35 @@ describe('shortFmtFilter', function () {
   }));
 
   it('should return the correct display from the number', function() {
-    expect(filter(0,2)).toEqual(0);
-    expect(filter(5,2)).toEqual(5);
+    expect(filter(0,2)).toEqual('0');
+    expect(filter(5,2)).toEqual('5.00');
     expect(filter(1024,0)).toEqual("1 K");
+    expect(filter(-1024,0)).toEqual("-1 K");
     expect(filter(1993,2)).toEqual("1.99 K");
-    expect(filter(1049901,5)).toEqual("1.0499 M"); 
+    expect(filter(-1993,2)).toEqual("-1.99 K");
+    expect(filter(1049901,5)).toEqual("1.04990 M");
+    expect(filter(-1049901,5)).toEqual("-1.04990 M");
     expect(filter(1909234901,2)).toEqual("1.91 B"); 
-
+    expect(filter(-1909234901,2)).toEqual("-1.91 B");
   });
 
-  it('should return NaN if bytes is not a number', function(){
-	expect(filter("0",2)).toEqual("NaN");
-	expect(filter([0],2)).toEqual("NaN");
-	expect(filter({number:0},0)).toEqual("NaN");
+  it('should return correct display if input can be parsed as a number', function(){
+  	expect(filter("0",2)).toEqual('0');
+  	expect(filter([0],2)).toEqual('0');
+    expect(filter([],2)).toEqual('0');
+  });
+
+  it('should return NaN if input cannot be parsed as a number', function(){
+    expect(filter({number:0},0)).toEqual(NaN);
   });
 
   it('should return NaN if decimal point is less than zero or not a number', function(){
-	expect(filter(0.45,-1)).toEqual("NaN");
-	expect(filter(-0.25,-101)).toEqual("NaN");
-	expect(filter(0.45,1.3)).toEqual("NaN");
-	expect(filter(0.45,"0")).toEqual("NaN");
-	expect(filter(0.45,[3])).toEqual("NaN");
-	expect(filter(0.45,{num : 4})).toEqual("NaN");	
+  	expect(filter(0.45,-1)).toEqual("NaN");
+  	expect(filter(-0.25,-101)).toEqual("NaN");
+  	expect(filter(0.45,1.3)).toEqual("NaN");
+  	expect(filter(0.45,"0")).toEqual("NaN");
+  	expect(filter(0.45,[3])).toEqual("NaN");
+  	expect(filter(0.45,{num : 4})).toEqual("NaN");	
   });
 
-});
+});