refactored mode's function

Author: TzeMingHo

Sprint-2/stretch/mode.js

@@ -8,29 +8,38 @@
 // refactor calculateMode by splitting up the code
 // into smaller functions using the stages above
 
-function calculateMode(list) {
-  // track frequency of each value
-  let freqs = new Map();
+function trackFrequency(list) {
+  let frequency = new Map();
 
   for (let num of list) {
     if (typeof num !== "number") {
       continue;
     }
 
-    freqs.set(num, (freqs.get(num) || 0) + 1);
+    frequency.set(num, (frequency.get(num) || 0) + 1);
   }
+  return frequency;
+}
 
-  // Find the value with the highest frequency
+function highestFrequency(frequencyArray) {
   let maxFreq = 0;
   let mode;
-  for (let [num, freq] of freqs) {
+  for (let [num, freq] of frequencyArray) {
     if (freq > maxFreq) {
       mode = num;
       maxFreq = freq;
     }
   }
-
   return maxFreq === 0 ? NaN : mode;
 }
 
+function calculateMode(list) {
+  // track frequency of each value
+  const frequencyArray = trackFrequency(list);
+
+  // Find the value with the highest frequency
+
+  return highestFrequency(frequencyArray);
+}
+
 module.exports = calculateMode;

Sprint-2/stretch/mode.test.js

@@ -13,20 +13,20 @@ const calculateMode = require("./mode.js");
 
 describe("calculateMode()", () => {
   test("returns the most frequent number in an array", () => {
-    const nums = [2, 4, 1, 2, 3, 2, 1];
+    const numArray = [2, 4, 1, 2, 3, 2, 1];
 
-    expect(calculateMode(nums)).toEqual(2);
+    expect(calculateMode(numArray)).toEqual(2);
   });
 
   test("returns the first mode in case of multiple modes", () => {
-    const nums = [1, 2, 2, 3, 3];
+    const numArray = [1, 2, 2, 3, 3];
 
-    expect(calculateMode(nums)).toEqual(2);
+    expect(calculateMode(numArray)).toEqual(2);
   });
 
   test("ignores non-number values", () => {
-    const nums = [1, 3, "2", 2, 3, null];
+    const numArray = [1, 3, "2", 2, 3, null];
 
-    expect(calculateMode(nums)).toEqual(3);
+    expect(calculateMode(numArray)).toEqual(3);
   });
 });