feat: add support for negative zeros

Author: vladimirivanoviliev

src/numbers/custom-number-format.js

@@ -87,7 +87,7 @@ function roundNumber(formatOptions) {
         number = round(number);
     }
 
-    if (formatOptions.negative && (number * -1) >= 0) {
+    if (formatOptions.negative && (number * -1) >= 0 && !formatOptions.negativeZero) {
         formatOptions.negative = false;
     }
 
@@ -102,7 +102,7 @@ function isConstantFormat(format) {
 function setValueSpecificFormat(formatOptions) {
     let { number, format } = formatOptions;
     format = format.split(LIST_SEPARATOR);
-    if (formatOptions.negative && format[1]) {
+    if ((formatOptions.negative || formatOptions.negativeZero) && format[1]) {
         format = format[1];
         formatOptions.hasNegativeFormat = true;
     } else if (number === 0) {
@@ -198,7 +198,7 @@ function replaceLiterals(number, literals) {
 }
 
 function replacePlaceHolders(formatOptions, info) {
-    const { start, end, negative, format, decimalIndex, lastZeroIndex, hasNegativeFormat, hasGroup } = formatOptions;
+    const { start, end, negative, negativeZero, format, decimalIndex, lastZeroIndex, hasNegativeFormat, hasGroup } = formatOptions;
     let number = formatOptions.number;
     const value = number.toString().split(POINT);
     const length = format.length;
@@ -209,7 +209,7 @@ function replacePlaceHolders(formatOptions, info) {
 
     number = format.substring(0, start);
 
-    if (negative && !hasNegativeFormat) {
+    if ((negative || negativeZero) && !hasNegativeFormat) {
         number += "-";
     }
 
@@ -273,6 +273,7 @@ export default function customNumberFormat(number, format, info) {
     const formatOptions = {
         negative: number < 0,
         number: Math.abs(number),
+        negativeZero: (1 / number === -Infinity),
         format: format
     };
 

src/numbers/standard-number-format.js

@@ -95,6 +95,7 @@ export default function standardNumberFormat(number, options, info) {
     value = round(value, maximumFractionDigits);
 
     const negative = value < 0;
+    const negativeZero = (1 / number === -Infinity);
 
     const parts = value.split(POINT);
 
@@ -122,7 +123,7 @@ export default function standardNumberFormat(number, options, info) {
         pattern = currencyUnitPattern(info, number);
     } else {
         const patterns = options.patterns;
-        pattern = negative ? patterns[1] || ("-" + patterns[0]) : patterns[0];
+        pattern = (negative || negativeZero) ? patterns[1] || ("-" + patterns[0]) : patterns[0];
     }
 
     if (pattern === NUMBER_PLACEHOLDER && !negative) {

test/numbers.js

@@ -41,6 +41,10 @@ describe('formatNumber', () => {
         expect(formatNumber(10000)).toEqual("10,000");
     });
 
+    it('should support minus zero', () => {
+        expect(formatNumber(-0)).toEqual("-0");
+    });
+
     it('should return empty string if no value is passed', () => {
         expect(formatNumber()).toEqual("");
     });
@@ -401,6 +405,10 @@ describe('custom formatting', () => {
         expect(formatNumber(10.9, '#')).toEqual("11");
     });
 
+    it('replaces whole part of the number', () => {
+        expect(formatNumber(-0, '#')).toEqual("-0");
+    });
+
     it('replaces # after 0 with 0', () => {
         expect(formatNumber(10.1, '#0####')).toEqual("00010");
     });
@@ -616,6 +624,22 @@ describe('parseNumber', () => {
         expect(parseNumber(value)).toEqual(value);
     });
 
+    it('returns zero if zero string is passed', () => {
+        expect(1 / parseNumber('0')).toEqual(Infinity);
+    });
+
+    it('returns negative zero if negative zero string is passed', () => {
+        expect(1 / parseNumber('-0')).toEqual(-Infinity);
+    });
+
+    it('returns negative zero if negative zero is passed', () => {
+        expect(1 / parseNumber(-0)).toEqual(-Infinity);
+    });
+
+    it('returns negative zero with accounting format', () => {
+        expect(1 / parseNumber('$(0.00)', undefined, '$0.00;$(0.00)')).toEqual(-Infinity);
+    });
+
     it('returns number if number is passed', () => {
         const value = 12.12;
         expect(parseNumber(value)).toEqual(value);