fix(numberFilter): format large numbers correctly

format large number to correct form instead of NAN.00 currently.
in previous code when first time we add the exponent with fractionSize
(number.toString()+'e'+fractionsize)
 and then convert it to an integer using ,
+(number.toString()+'e'+fractionsize)
when the number is very large and number will be represented by using exponent. for example 12345868059685210000 will be represented by 1.234586805968521e+21. as getting string in exponent is not handles, we get the number as NAN.
Handle when the number is being represented in exponent form, by adjusting exponent of number with fraction size:

Closes angular#8674

src/ng/filter/filters.js

@@ -118,6 +118,12 @@ function numberFilter($locale) {
   };
 }
 
+function getExponentString(numberString,fractionSize) {
+  var numberArray = numberString.split('e'),
+  fractionUsed = +fractionSize;
+  return (numberArray[0] + 'e' + (numberArray[1] ? (+numberArray[1] + fractionUsed) : fractionUsed));
+}
+
 var DECIMAL_SEP = '.';
 function formatNumber(number, pattern, groupSep, decimalSep, fractionSize) {
   if (number == null || !isFinite(number) || isObject(number)) return '';
@@ -151,7 +157,7 @@ function formatNumber(number, pattern, groupSep, decimalSep, fractionSize) {
     // safely round numbers in JS without hitting imprecisions of floating-point arithmetics
     // inspired by:
     // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/round
-    number = +(Math.round(+(number.toString() + 'e' + fractionSize)).toString() + 'e' + -fractionSize);
+    number = +(getExponentString(Math.round(+(getExponentString(number.toString(),fractionSize))).toString(),-fractionSize));
 
     var fraction = ('' + number).split(DECIMAL_SEP);
     var whole = fraction[0];

test/ng/filter/filtersSpec.js

@@ -59,6 +59,12 @@ describe('filters', function() {
       expect(num).toBe('1.1112');
     });
 
+    it('should format large number',function() {
+      pattern.gsize = 2;
+      var num = formatNumber(12345868059685210000, pattern, ',', '.', 2);
+      expect(num).toBe('12,345,868,059,685,210,000.00');
+    });
+
     it('should format according different separators', function() {
       var num = formatNumber(1234567.1, pattern, '.', ',', 2);
       expect(num).toBe('1.234.567,10');