Merge pull request #114 from Exabyte-io/feature/SOF-7597

feature/SOF 7597

Author: VsevolodX

dist/js/math.d.ts

@@ -26,6 +26,11 @@ export type FormatOptions = mathjs.FormatOptions;
 export type Help = mathjs.Help;
 export type MathJsChain = mathjs.MathJsChain;
 export type MathJsJson = mathjs.MathJsJson;
+export declare enum RoundingMethod {
+    Bankers = "bankers",
+    HalfAwayFromZero = "halfAwayFromZero"
+}
+export declare const roundCustom: (value: number, decimals?: number, method?: RoundingMethod) => number;
 /**
  * @summary Wrapper for native [Number.toPrecision](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_objects/Number/toPrecision) method.
  * Returns a string representing the Number object to the specified precision.
@@ -58,6 +63,8 @@ export declare const math: {
     calculateSegmentsBetweenPoints3D: (point1: (string | number)[], point2: (string | number)[], n: number | string) => number[][];
     roundValueToNDecimals: (value: number, decimals?: number) => number;
     numberToPrecision: typeof numberToPrecision;
+    roundCustom: (value: number, decimals?: number, method?: RoundingMethod) => number;
+    RoundingMethod: typeof RoundingMethod;
     e: number;
     pi: number;
     i: number;

dist/js/math.js

@@ -3,7 +3,7 @@ var __importDefault = (this && this.__importDefault) || function (mod) {
     return (mod && mod.__esModule) ? mod : { "default": mod };
 };
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.math = void 0;
+exports.math = exports.roundCustom = exports.RoundingMethod = void 0;
 exports.numberToPrecision = numberToPrecision;
 /* eslint-disable */
 const mathjs_1 = __importDefault(require("mathjs"));
@@ -170,6 +170,39 @@ const combinationsFromIntervals = (arrA, arrB, arrC) => {
 const roundValueToNDecimals = (value, decimals = 3) => {
     return parseFloat(value.toFixed(decimals));
 };
+// See: https://en.wikipedia.org/wiki/Rounding
+var RoundingMethod;
+(function (RoundingMethod) {
+    RoundingMethod["Bankers"] = "bankers";
+    RoundingMethod["HalfAwayFromZero"] = "halfAwayFromZero";
+})(RoundingMethod || (exports.RoundingMethod = RoundingMethod = {}));
+const roundCustom = (value, decimals = 0, method = RoundingMethod.HalfAwayFromZero) => {
+    const factor = Math.pow(10, decimals);
+    const scaledValue = value * factor;
+    const absValue = Math.abs(scaledValue);
+    const sign = scaledValue < 0 ? -1 : 1;
+    let roundedAbs;
+    switch (method) {
+        case RoundingMethod.HalfAwayFromZero:
+            roundedAbs = Math.round(absValue);
+            break;
+        case RoundingMethod.Bankers:
+            const floorValue = Math.floor(absValue);
+            const fractional = absValue - floorValue;
+            if (Math.abs(fractional - 0.5) < Number.EPSILON) {
+                // Round to even
+                roundedAbs = floorValue % 2 === 0 ? floorValue : floorValue + 1;
+            }
+            else {
+                roundedAbs = Math.round(absValue);
+            }
+            break;
+        default:
+            throw new Error(`Unsupported rounding method: ${method}`);
+    }
+    return (roundedAbs * sign) / factor;
+};
+exports.roundCustom = roundCustom;
 /**
  * @summary Returns n splits of the passed segment.
  */
@@ -227,4 +260,6 @@ exports.math = {
     calculateSegmentsBetweenPoints3D,
     roundValueToNDecimals,
     numberToPrecision,
+    roundCustom: exports.roundCustom,
+    RoundingMethod,
 };

src/js/math.ts

@@ -216,6 +216,46 @@ const roundValueToNDecimals = (value: number, decimals = 3) => {
     return parseFloat(value.toFixed(decimals));
 };
 
+// See: https://en.wikipedia.org/wiki/Rounding
+export enum RoundingMethod {
+    Bankers = "bankers",
+    HalfAwayFromZero = "halfAwayFromZero",
+}
+
+export const roundCustom = (
+    value: number,
+    decimals = 0,
+    method = RoundingMethod.HalfAwayFromZero,
+) => {
+    const factor = Math.pow(10, decimals);
+    const scaledValue = value * factor;
+    const absValue = Math.abs(scaledValue);
+    const sign = scaledValue < 0 ? -1 : 1;
+
+    let roundedAbs: number;
+
+    switch (method) {
+        case RoundingMethod.HalfAwayFromZero:
+            roundedAbs = Math.round(absValue);
+            break;
+        case RoundingMethod.Bankers:
+            const floorValue = Math.floor(absValue);
+            const fractional = absValue - floorValue;
+
+            if (Math.abs(fractional - 0.5) < Number.EPSILON) {
+                // Round to even
+                roundedAbs = floorValue % 2 === 0 ? floorValue : floorValue + 1;
+            } else {
+                roundedAbs = Math.round(absValue);
+            }
+            break;
+        default:
+            throw new Error(`Unsupported rounding method: ${method}`);
+    }
+
+    return (roundedAbs * sign) / factor;
+};
+
 /**
  * @summary Returns n splits of the passed segment.
  */
@@ -280,4 +320,6 @@ export const math = {
     calculateSegmentsBetweenPoints3D,
     roundValueToNDecimals,
     numberToPrecision,
+    roundCustom,
+    RoundingMethod,
 };

tests/js/math.ts

@@ -0,0 +1,30 @@
+import { expect } from "chai";
+
+import { math } from "../../src/js/math";
+
+describe("Math Tests", () => {
+    it("should round according to specified method", () => {
+        const [value1, value2, value3, value4] = [0.5, 1.5, -0.5, -1.5];
+        const [expectedBankers1, expectedBankers2, expectedBankers3, expectedBankers4] = [
+            0, 2, 0, -2,
+        ];
+        const [expectedAway1, expectedAway2, expectedAway3, expectedAway4] = [1, 2, -1, -2];
+        const n = 0;
+        expect(math.roundCustom(value1, n, math.RoundingMethod.Bankers)).to.equal(expectedBankers1);
+        expect(math.roundCustom(value2, n, math.RoundingMethod.Bankers)).to.equal(expectedBankers2);
+        expect(math.roundCustom(value3, n, math.RoundingMethod.Bankers)).to.equal(expectedBankers3);
+        expect(math.roundCustom(value4, n, math.RoundingMethod.Bankers)).to.equal(expectedBankers4);
+        expect(math.roundCustom(value1, n, math.RoundingMethod.HalfAwayFromZero)).to.equal(
+            expectedAway1,
+        );
+        expect(math.roundCustom(value2, n, math.RoundingMethod.HalfAwayFromZero)).to.equal(
+            expectedAway2,
+        );
+        expect(math.roundCustom(value3, n, math.RoundingMethod.HalfAwayFromZero)).to.equal(
+            expectedAway3,
+        );
+        expect(math.roundCustom(value4, n, math.RoundingMethod.HalfAwayFromZero)).to.equal(
+            expectedAway4,
+        );
+    });
+});