From 23ee7e3f2a0cb484ea845ce88af27ae7d5fece55 Mon Sep 17 00:00:00 2001
From: SoundLogic <soundlogic@wavesandbox.com>
Date: Thu, 19 Feb 2015 14:00:24 -0500
Subject: [PATCH] made changes as discussed here:
 https://github.com/a8m/angular-filter/issues/74 and updated tests

---
 src/_filter/math/math.js           | 12 ++++++++-
 src/_filter/math/short-fmt.js      | 42 ++++++++++++++++--------------
 test/spec/filter/math/short-fmt.js | 37 +++++++++++++++-----------
 3 files changed, 56 insertions(+), 35 deletions(-)

diff --git a/src/_filter/math/math.js b/src/_filter/math/math.js
index 0ad77b9..97a3af9 100644
--- a/src/_filter/math/math.js
+++ b/src/_filter/math/math.js
@@ -8,6 +8,16 @@
 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;
 
   }]);
diff --git a/src/_filter/math/short-fmt.js b/src/_filter/math/short-fmt.js
index 67b963a..1295875 100644
--- a/src/_filter/math/short-fmt.js
+++ b/src/_filter/math/short-fmt.js
@@ -11,23 +11,27 @@
 
 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, $math) + ' B';
-          }
+.filter('shortFmt', ['$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";
-	  }
-	}
-}]);
\ No newline at end of file
+            } else {
+                return 'NaN';
+            }
+        })
+    }]);
diff --git a/test/spec/filter/math/short-fmt.js b/test/spec/filter/math/short-fmt.js
index 3308a8c..d07c5c7 100644
--- a/test/spec/filter/math/short-fmt.js
+++ b/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");	
   });
   
-});
+});
\ No newline at end of file