Floating point errors

accounting.js

@@ -215,12 +215,39 @@
 	 */
 	var toFixed = lib.toFixed = function(value, precision) {
 		precision = checkPrecision(precision, lib.settings.number.precision);
-		var power = Math.pow(10, precision);
+		var unformattedValue = lib.unformat(value).toString();
 
-		// Multiply up by precision, round accurately, then divide and use native toFixed():
-		return (Math.round(lib.unformat(value) * power) / power).toFixed(precision);
-	};
+		if(unformattedValue == 0) {
+			return Number(0).toFixed(precision);
+		}
+
+		var number = unformattedValue.split(".");
+		var integer = number[0];
+
+		var mantissa = number.length > 1 ? number[1] : "";
+		if(mantissa.length < precision) {
+			var diff = precision - mantissa.length;
+			for(var i=0; i<diff; i++)
+				mantissa += "0";
+		}
+
+		var x = parseInt(mantissa[precision]);
+		var newMantissa = mantissa.substr(0,precision);
+		var fullNumber = Number([integer,newMantissa].join(""));
 
+		if(x > 4) {
+			fullNumber += 1;
+		}
+
+		var newValue = fullNumber.toString();
+
+		if(precision == 0)
+			return newValue;
+
+		var dotIdx = newValue.length - precision;
+		newValue = (newValue.slice(0,dotIdx)||0) + '.' + (newValue.slice(dotIdx)||0); 
+		return newValue;
+	};
 
 	/**
 	 * Format a number, with comma-separated thousands and custom precision/decimal places

tests/jasmine/core/formatMoneySpec.js

@@ -2,6 +2,7 @@ describe('formatMoney()', function(){
 
     it('should work for small numbers', function(){
 
+        expect( accounting.formatMoney(0) ).toBe( '$0.00' );
         expect( accounting.formatMoney(123) ).toBe( '$123.00' );
         expect( accounting.formatMoney(123.45) ).toBe( '$123.45' );
         expect( accounting.formatMoney(12345.67) ).toBe( '$12,345.67' );

tests/jasmine/core/formatNumberSpec.js

@@ -3,20 +3,25 @@ describe('formatNumber', function(){
     describe('rounding and enforce precision', function(){
 
         it('should enforce precision and round values', function(){
-
+
+            expect( accounting.formatNumber(0, 2) ).toBe( '0.00' );
             expect( accounting.formatNumber(123.456789, 0) ).toBe( '123' );
             expect( accounting.formatNumber(123.456789, 1) ).toBe( '123.5' );
             expect( accounting.formatNumber(123.456789, 2) ).toBe( '123.46' );
             expect( accounting.formatNumber(123.456789, 3) ).toBe( '123.457' );
             expect( accounting.formatNumber(123.456789, 4) ).toBe( '123.4568' );
             expect( accounting.formatNumber(123.456789, 5) ).toBe( '123.45679' );
 
+            expect( accounting.formatNumber(129.9, 0) ).toBe( '130' );
+            expect( accounting.formatNumber(129.99, 1) ).toBe( '130.0' );
+
         });
 
-        it('should fix floting point rounding error', function(){
+        it('should fix floating point rounding error', function(){
 
             expect( accounting.formatNumber(0.615, 2) ).toBe( '0.62' );
             expect( accounting.formatNumber(0.614, 2) ).toBe( '0.61' );
+            expect( accounting.formatNumber(8.325, 2) ).toBe( '8.33' );
 
         });