Add calculateMedian function with tests for even and odd length arrays

Author: HoussamLh

prep/mean.js

@@ -3,4 +3,7 @@ function calculateMean(list) {
   return sum / list.length;
 }
 
-module.exports = calculateMean;
+module.exports = calculateMean;
+
+
+// module.exports = { calculateMean };

prep/median.js

@@ -1,3 +1,4 @@
+/*
 // prep/median.js
 function calculateMedian(list) {
   const middleIndex = Math.floor(list.length / 2);
@@ -6,4 +7,23 @@ function calculateMedian(list) {
   return median;
 }
 module.exports = calculateMedian;
+*/
+ 
+// We clone the array with [...numbers] 
+// before sorting to avoid mutating the original input.
+
+
+function calculateMedian(numbers) {
+  const sorted = [...numbers].sort((a, b) => a - b);
+  const mid = Math.floor(sorted.length / 2);
+
+  if (sorted.length % 2 === 0) {
+    return (sorted[mid - 1] + sorted[mid]) / 2;
+  } else {
+    return sorted[mid];
+  }
+}
+
+module.exports = calculateMedian;
+
 

prep/median.test.js

@@ -1,5 +1,9 @@
+// const { calculateMedian } = require("./median");
 const calculateMedian = require("./median");
+
+
 const calculateMean = require("./mean");
+// const { calculateMean } = require("./mean");
 
 test("calculates the median of a list of odd length", () => {
   const list = [10, 20, 30, 50, 60];
@@ -9,6 +13,22 @@ test("calculates the median of a list of odd length", () => {
   expect(currentOutput).toEqual(targetOutput);
 })
 
+test("calculates the median of an odd-length array", () => {
+  const list = [3, 50, 7];
+  const currentOutput = calculateMedian(list); // sorted = [3, 7, 50], median = 7
+  const expectedOutput = 7;
+
+  expect(currentOutput).toEqual(expectedOutput);
+});
+
+test("calculates the median of a list of odd length", () => {
+  const list = [10, 20, 30, 40];
+  const currentOutput = calculateMedian(list);
+  const targetOutput = 25;
+
+  expect(currentOutput).toEqual(targetOutput);
+}) 
+
 // Both functions access the same array 
 // because JavaScript passes objects and 
 // arrays by reference — they all point to the same memory location.
@@ -18,4 +38,9 @@ const median = calculateMedian(salaries);
 const mean = calculateMean(salaries);
 console.log(salaries, "<--- salaries input before we call calculateMean");
 console.log(`The median salary is ${median}`);
-console.log(`The mean salary is ${mean}`);
+console.log(`The mean salary is ${mean}`);
+
+
+
+
+