feat: add calculate median

Maths/CalculateMedian.ts

@@ -0,0 +1,30 @@
+import { IsEven } from "./IsEven";
+
+/**
+ * @function calculateMedian
+ * @description This script will find the meadian value of a array of numbers.
+ * @param {number[]} numbers - Array of numeric values
+ * @return {number} - median of input numbers
+ * @see [Median](https://en.wikipedia.org/wiki/Median)
+ * @example calculateMedian([1, 2, 4, 5, 8]) = 4
+ * @example calculateMedian([1, 2, 4, 5]) = 3
+ */
+
+
+export const calculateMedian = (numbers: number[]): number => {
+  if (numbers.length < 1) {
+    throw new TypeError("Invalid Input");
+  }
+
+  let sortedArray: number[] = numbers.sort((n1,n2) => n1 - n2);
+  const totalNumbers = sortedArray.length;
+
+  if (IsEven(totalNumbers)){
+    let index = (totalNumbers) / 2;
+    return (sortedArray[index - 1] + sortedArray[index]) / 2;
+  } else {
+    let index = (totalNumbers + 1) / 2;
+    return sortedArray[index - 1]; 
+  }
+
+};

Maths/test/CalculateMedian.test.ts

@@ -0,0 +1,22 @@
+import { calculateMedian } from "../CalculateMedian";
+
+describe("Tests for CalculateMedian", () => {
+  it("should be a function", () => {
+    expect(typeof calculateMedian).toEqual("function");
+  });
+
+  it("should throw error for invalid input", () => {
+    expect(() => calculateMedian([])).toThrow();
+  });
+
+  it("should return the median of an array of numbers - even length", () => {
+    const medianFunction = calculateMedian([1, 2, 3, 4]);
+    expect(medianFunction).toBe(2.5);
+  });
+
+  it("should return the median of an array of numbers - odd length", () => {
+    const medianFunction = calculateMedian([1, 2, 3, 4, 6, 8, 9]);
+    expect(medianFunction).toBe(4);
+  });
+
+});