fix(formatNumber): remove trailing zeros after rounding

Author: danielkaradachki

src/numbers/custom-number-format.js

@@ -14,6 +14,7 @@ const ZERO = "0";
 const EMPTY = "";
 
 const literalRegExp = /(\\.)|(['][^']*[']?)|(["][^"]*["]?)/g;
+const trailingZerosRegExp = /(\.(?:[0-9]*[1-9])?)0+$/g;
 const commaRegExp = /\,/g;
 
 function setFormatLiterals(formatOptions) {
@@ -31,6 +32,21 @@ function setFormatLiterals(formatOptions) {
     }
 }
 
+function trimTrailingZeros(value, lastZero) {
+    let result;
+    if (lastZero === 0) {
+        result = value.replace(trailingZerosRegExp, '$1');
+    } else {
+        result = value.replace(new RegExp(`(\\.[0-9]{${ lastZero }}[1-9]*)0+$`, 'g'), '$1');
+    }
+
+    if (result.charAt(result.length - 1) === POINT) {
+        result = result.substr(0, result.length - 1);
+    }
+
+    return result;
+}
+
 function roundNumber(formatOptions) {
     let { number, format } = formatOptions;
     let decimalIndex = format.indexOf(POINT);
@@ -49,24 +65,30 @@ function roundNumber(formatOptions) {
         }
         fraction = fraction.split(POINT)[1] || EMPTY;
 
-        let idx = fraction.length;
+        let precision = fraction.length;
+        let trailingZeros = -1;
 
         if (!hasZero && !hasSharp) {
             formatOptions.format = format.substring(0, decimalIndex) + format.substring(decimalIndex + 1);
             decimalIndex = -1;
-            idx = 0;
+            precision = 0;
         } else if (hasZero && zeroIndex > sharpIndex) {
-            idx = zeroIndex;
+            precision = zeroIndex;
         } else if (sharpIndex > zeroIndex) {
-            if (hasSharp && idx > sharpIndex) {
-                idx = sharpIndex;
-            } else if (hasZero && idx < zeroIndex) {
-                idx = zeroIndex;
+            if (hasSharp && precision > sharpIndex) {
+                precision = sharpIndex;
+            } else if (hasZero && precision < zeroIndex) {
+                precision = zeroIndex;
             }
+
+            trailingZeros = hasZero ? zeroIndex : 0;
         }
 
-        if (idx > -1) {
-            number = round(number, idx);
+        if (precision > -1) {
+            number = round(number, precision);
+            if (trailingZeros > -1) {
+                number = trimTrailingZeros(number, trailingZeros);
+            }
         }
     } else {
         number = round(number);

test/numbers.js

@@ -447,6 +447,13 @@ describe('custom formatting', () => {
         expect(formatNumber(3.235555, "0.#0")).toEqual("3.24");
     });
 
+    it("removes trailing zeros after rounding", () => {
+        expect(formatNumber(0.016999999999, "#.#####")).toEqual("0.017");
+        expect(formatNumber(0.016999999999, "#.0000#")).toEqual("0.0170");
+        expect(formatNumber(1.999, "0.0#")).toEqual("2.0");
+        expect(formatNumber(1.999, "0.#")).toEqual("2");
+    });
+
     it("removes decimal part if no number placeholder", () => {
         expect(formatNumber(3.222, "0.")).toEqual("3");
     });
@@ -460,7 +467,7 @@ describe('custom formatting', () => {
     });
 
     it("applies negative format rounding", () => {
-        expect(formatNumber(-0.001, "####;-(#.#)")).toEqual("-(0.0)");
+        expect(formatNumber(-0.001, "####;-(#.#)")).toEqual("-(0)");
     });
 
     it("toString decimal number -1000 with negative format", () => {
@@ -472,7 +479,7 @@ describe('custom formatting', () => {
     });
 
     it("clears negative sign if rounded number is positive", () => {
-        expect(formatNumber(-0.00001, "#.##")).toEqual("0.00");
+        expect(formatNumber(-0.00001, "#.##")).toEqual("0");
     });
 
     it("formats 0", () => {