add decimal option to percentage function

package.json

@@ -1,6 +1,6 @@
 {
   "name": "ts-utily",
-  "version": "1.2.3",
+  "version": "1.2.4",
   "description": "Typescript utils library",
   "homepage": "https://github.com/kemotx90/ts-utily#readme",
   "main": "dist/ts-utily.js",

src/utils/number-utils.ts

@@ -24,12 +24,16 @@ export const isNumber = <T>(value: T): boolean => {
     }
 }
 
+
 /**
- * The function calculates the percentage of a value in relation to a total value.
- * @param {number} value - The value parameter represents the specific value that you want to calculate the percentage of. It is a number that you want to find the percentage of in relation to the totalValue.
- * @param {number} totalValue - The total value represents the maximum value or the total amount that you want to calculate the percentage of.
- * @returns a number, which is the calculated percentage value.
+ * Calculates the percentage of a value relative to a total value, rounded to a specified number of decimal places.
+ *
+ * @param {number} value - The part value to calculate the percentage for.
+ * @param {number} totalValue - The total value that represents 100%.
+ * @param {number} [decimals=0] - The number of decimal places to round the result to.
+ * @returns {number} - The calculated percentage.
  */
-export const percentage = (value: number, totalValue: number): number => {
-    return Math.round((value / totalValue) * 100);
+export const percentage = (value: number, totalValue: number, decimals: number = 0): number => {
+    const factor = Math.pow(10, decimals);
+    return Math.round((value / totalValue) * 100 * factor) / factor;
 }

test/number-utils.spec.ts

@@ -1,6 +1,6 @@
 import {isNumber, percentage, toNumber} from "../src/index";
 
-
+// Tests for the toNumber function
 test('to number 0, 100, -100, 1.2', () => {
     expect(toNumber('0')).toBe(0);
     expect(toNumber(100)).toBe(100);
@@ -15,6 +15,7 @@ test('not number {}, test, u12, 1.2n', () => {
     expect(toNumber('1.2n')).toBe(0);
 });
 
+// Tests for the isNumber function
 test('is number 0, 100, -100, 1.2', () => {
     expect(isNumber('0')).toBe(true);
     expect(isNumber(100)).toBe(true);
@@ -31,8 +32,44 @@ test('is not number {}, test, u12, 1.2n', () => {
     expect(isNumber(undefined)).toBe(false);
 });
 
-test('percentage (10,100), (150.34,300.22), (322,544)', () => {
+// Tests for the percentage function
+/*
+ * The `percentage` function calculates the percentage of a value relative to a total value,
+ * rounded to a specified number of decimal places.
+ */
+
+test('percentage of 10 out of 100 is 10%', () => {
     expect(percentage(10, 100)).toBe(10);
-    expect(percentage(150.34, 300.22)).toBe(50);
-    expect(percentage(322, 544)).toBe(59);
+});
+
+test('percentage of 150.34 out of 300.22 is around 50%', () => {
+    expect(percentage(150.34, 300.22)).toBeCloseTo(50, 0);
+});
+
+test('percentage of 322 out of 544 is around 59.19 with 2 decimals', () => {
+    expect(percentage(322, 544, 2)).toBeCloseTo(59.19, 2);
+});
+
+test('percentage of 1 out of 3 is around 33.33 with 2 decimals', () => {
+    expect(percentage(1, 3, 2)).toBeCloseTo(33.33, 2);
+});
+
+test('percentage of 25 out of 25 is 100%', () => {
+    expect(percentage(25, 25)).toBe(100);
+});
+
+test('percentage of 0 out of 25 is 0%', () => {
+    expect(percentage(0, 25)).toBe(0);
+});
+
+test('percentage with 0 total value returns Infinity', () => {
+    expect(percentage(25, 0)).toBe(Infinity);
+});
+
+test('percentage with negative value and total', () => {
+    expect(percentage(-50, -100)).toBe(50);
+});
+
+test('percentage with mixed positive value and negative total', () => {
+    expect(percentage(50, -200)).toBe(-25);
 });