feat: added implementation for average mode

Maths/AverageMode.js

@@ -0,0 +1,34 @@
+/*
+  A program to get the mode of the given array of data.
+
+  In statistics, mode is the most often occurring value in a set of data values,
+  it may or may not have the same numerical value as mean or median in a normal distribution, depending on how skewed the distribution is.
+  Mode is not necessarily unique, since two values may appear the same number of times in a set of values, in which case, both shall be considered to be modes.
+
+  Wikipedia: https://en.wikipedia.org/wiki/Mode_(statistics)
+*/
+
+/**
+ * @param {Array<any>} data 
+ */
+const averageMode = (data) => {
+  const counts = new Map()
+  const mode = []
+  let max = 0
+
+  for(const entry of data) {
+    const count = counts.get(entry) ?? 0
+    counts.set(entry, count + 1)
+
+    if(max < count + 1)
+      max = count + 1
+  }
+
+  for(const [key, value] of counts.entries())
+    if(max === value)
+      mode.push(key)
+
+  return mode.sort()
+}
+
+export { averageMode }

Maths/test/AverageMode.test.js

@@ -0,0 +1,21 @@
+import { averageMode } from '../AverageMode'
+
+test('should return the mode of an array of numbers:', () => {
+  const mode = averageMode([1, 2, 6, 4, 5])
+  expect(mode).toEqual([1, 2, 4, 5, 6])
+})
+
+test('should return the mode of an array of numbers:', () => {
+  const mode = averageMode([2, 3, 4, 5, 3, 4, 2, 5, 2, 2, 4, 2, 2, 2])
+  expect(mode).toEqual([2])
+})
+
+test('should return the mode of an array of numbers:', () => {
+  const mode = averageMode(['x', 'x' , 'y', 'y', 'z'])
+  expect(mode).toEqual(['x', 'y'])
+})
+
+test('should return the mode of an array of numbers:', () => {
+  const mode = averageMode([3, 4, 5, 3, 4, 2, 5, 2, 2, 4, 4, 4, 2, 2, 4, 2])
+  expect(mode).toEqual([2, 4])
+})