Manchester | 26-ITP-Jan | Ofonime Edak | Sprint 1 | Data group by Ofonimeedak · Pull Request #1045 · CodeYourFuture/Module-Data-Groups

Ofonimeedak · 2026-03-19T12:05:59Z

Self checklist

I have titled my PR with Region | Cohort | FirstName LastName | Sprint | Assignment Title
My changes meet the requirements of the task
I have tested my changes
My changes follow the style guide

Changelist

I have made changes to the following files, sum.js,include.js and all test cases
I have followed the acceptance criteria for all katas
This PR contains functions for de-duplication and summation of arrays
It also contained a refactored function and different test cases

cjyuan

Why not practice "committing files one by one, on purpose, and for a reason"?
In VSCode, you can select which file to stage, and commit only the staged file.
See: https://www.youtube.com/watch?v=z5jZ9lrSpqk&t=705 (At around 12:50 minute marker, the video shows how to stage a single file).

cjyuan · 2026-03-19T22:07:40Z

Sprint-1/fix/median.js

+  const numbers = [];
+  for (const x of list) {
+    if (typeof x === "number" && !isNaN(x)) {
+      numbers.push(Number(x));
+    }
+  }


The code work.

This is also a good opportunity to practice using the array's .filter() method to simplify the code on lines 11-16.

cjyuan · 2026-03-19T22:09:33Z

Sprint-1/implement/dedupe.js

+function dedupe(arr) {
+
+if(arr.length===0) return arr;
+const dedupeArray=[]
+for(let i=0;i<arr.length;i++){
+
+    if(!dedupeArray.includes(arr[i])){
+        dedupeArray.push(arr[i])
+    }
+}
+return dedupeArray;
+
+
+}


Code is not consistently formatted.

Have you installed the prettier VSCode extension and enabled "Format on save/paste" on VSCode,
as recommended in
https://github.com/CodeYourFuture/Module-Structuring-and-Testing-Data/blob/main/readme.md
?

cjyuan · 2026-03-19T22:10:34Z

Sprint-1/implement/dedupe.test.js

+  // Given an array with no duplicates
+  // Then it should return a copy of the original array
+  [
+    { input: [1, 2, 3, 4], expected: [1, 2, 3, 4] },
+    {
+      input: ["apples", "banana", "orange"],
+      expected: ["apples", "banana", "orange"],
+    },
+    { input: [-1, 7, 1], expected: [-1, 7, 1] },
+  ].forEach(({ input, expected }) =>
+    it(`should return same input values [${input}] without duplicate`, () => {
+      expect(dedupe(input)).toEqual(expected);
+    }));


This test should fail if the function returns the original array (instead of a copy of the original array).

The current test checks only if both the original array and the returned array contain identical elements.
In order to validate the returned array is a different array, we need an additional check.

Can you find out what this additional check is?

cjyuan · 2026-03-19T22:17:05Z

Sprint-1/implement/max.test.js

 // Given an empty array
 // When passed to the max function
 // Then it should return -Infinity
 // Delete this test.todo and replace it with a test.
-test.todo("given an empty array, returns -Infinity");
+describe("findMax()", () => {
+  [{ input: [], expected: Infinity }].forEach(({ input, expected }) =>


According to the spec on line 17, the function is expected to return -Infinity when given an empty array.

cjyuan · 2026-03-19T23:05:29Z

Sprint-1/implement/max.js

+  if (elements.length === 0) return Infinity;
+  const number = [];
+  for (let i = 0; i < elements.length; i++) {
+    if (typeof elements[i] === "number" && !Number.isNaN(elements[i])) {
+      number.push(elements[i]);
+    }
+  }
+  if (number.length === 0) return "invalid elements";


Could consider treating both empty array and arrays that contains only non-numeric values as
"arrays that do not contain any number".

cjyuan · 2026-03-19T23:06:47Z

Sprint-1/implement/max.test.js

+  // Given an array with non-number values
+  // When passed to the max function
+  // Then it should return the max and ignore non-numeric values
+  [
+    { input: ["edak", "ofonime", "", "@", -4, 10, 6, 50, -100], expected: 50 },
+  ].forEach(({ input, expected }) =>
+    it(`should return max numerical value from the array`, () => {
+      expect(findMax(input)).toEqual(expected);
+    })
+  );
+
+  // Given an array with only non-number values
+  // When passed to the max function
+  // Then it should return the least surprising value given how it behaves for all other inputs
+  [{ input: ["peter", "", "@", "Hi"], expected: "invalid elements" }].forEach(
+    ({ input, expected }) =>
+      it(`should return "invalid elements" for non-numeric values`, () => {
+        expect(findMax(input)).toEqual(expected);
+      })
+  );
+});


When a string representing a valid numeric literal (for example, "300") is compared to a number,
JavaScript first converts the string into its numeric equivalent before performing the comparison.
As a result, the expression 20 < "300" evaluates to true.

To test if the function can correctly ignore non-numeric values,
consider including a string such as "300" in the relevant test cases.

cjyuan · 2026-03-19T23:08:52Z

Sprint-1/implement/sum.test.js

+  [{ input: [0.5, 0.2, 0.11, 0.89, 0.3], expected: 2 }].forEach(
+    ({ input, expected }) =>
+      it(`should return ${expected} for [${input}]`, () => {
+        expect(sum(input)).toEqual(expected);
+      })
+  );


Decimal numbers in most programming languages (including JS) are internally represented in "floating point number" format. Floating point arithmetic is not exact. For example, the result of 46.5678 - 46 === 0.5678 is false because 46.5678 - 46 only yield a value that is very close to 0.5678. Even changing the order in which the program add/subtract numbers can yield different values.

So the following could happen

expect( 1.2 + 0.6 + 0.005 ).toEqual( 1.805 ); // This fail expect( 1.2 + 0.6 + 0.005 ).toEqual( 1.8049999999999997 ); // This pass expect( 0.005 + 0.6 + 1.2 ).toEqual( 1.8049999999999997 ); // This fail console.log(1.2 + 0.6 + 0.005 == 1.805); // false console.log(1.2 + 0.6 + 0.005 == 0.005 + 0.6 + 1.2); // false

Can you find a more appropriate way to test a value (that involves decimal number calculations) for equality?

Suggestion: Look up

Checking equality in floating point arithmetic in JavaScript

Checking equality in floating point arithmetic with Jest

cjyuan · 2026-03-19T23:10:22Z

Sprint-1/implement/sum.test.js

+  // Then it should ignore the non-numerical values and return the sum of the numerical elements
+
+  [
+    { input: ["evan", 3, "mike", 20, 6, "", "/", , , 20], expected: 49 },


Better to explicitly specify undefined instead of leaving the element blank.

write and implement function and test case

735f291

Ofonimeedak added 📅 Sprint 1 Assigned during Sprint 1 of this module Needs Review Trainee to add when requesting review. PRs without this label will not be reviewed. Module-Data-Groups The name of the module. labels Mar 19, 2026

cjyuan reviewed Mar 19, 2026

View reviewed changes

cjyuan added Reviewed Volunteer to add when completing a review with trainee action still to take. and removed Needs Review Trainee to add when requesting review. PRs without this label will not be reviewed. labels Mar 19, 2026

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Manchester | 26-ITP-Jan | Ofonime Edak | Sprint 1 | Data group#1045

Manchester | 26-ITP-Jan | Ofonime Edak | Sprint 1 | Data group#1045
Ofonimeedak wants to merge 1 commit intoCodeYourFuture:mainfrom
Ofonimeedak:datagroup/sprint1-coursework

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Ofonimeedak commented Mar 19, 2026

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