Manchester | 25-ITP-Sep | Mahtem T. Mengstu | Sprint 2 |Sprint-2-courseWork by Mahtem · Pull Request #913 · CodeYourFuture/Module-Data-Groups

Mahtem · 2025-12-06T14:25:26Z

Learners, PR Template

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

In the data-groups module Sprint -2 exercises. functions implemented and tests passed.

Questions

Questions and review requests will be done in slack.

cjyuan · 2025-12-08T00:59:29Z

Sprint-2/debug/recipe.js

 console.log(`${recipe.title} serves ${recipe.serves}
  ingredients:
-${recipe}`);
+${recipe.ingredients.join(", ")}`);


Can you make each ingredient to appear on a new line (to meet the specification on line 4)?

Can you make each ingredient to appear on a new line (to meet the specification on line 4)?

Thank you @cjyuan I have modified "${recipe.ingredients.join("\n")}`) to make ingredients appear on new line.

cjyuan · 2025-12-08T01:00:03Z

Sprint-2/implement/contains.js

+  if (typeof obj !== "object" || obj === null || Array.isArray(obj)) {
+    return false;
+}
+return key in obj;


Consider the following two approaches for determining if an object contains a property:

let obj = {}, propertyName = "toString"; console.log( propertyName in obj ); // true console.log( Object.hasOwn(obj, propertyName) ); // false

Which of these approaches suits your needs better?
For more info, you can look up JS "in" operator vs Object.hasOwn.

Consider the following two approaches for determining if an object contains a property:

let obj = {}, propertyName = "toString"; console.log( propertyName in obj ); // true console.log( Object.hasOwn(obj, propertyName) ); // false

Which of these approaches suits your needs better? For more info, you can look up JS "in" operator vs Object.hasOwn.

Thank you, I have come to know that, console.log( propertyName in obj ); inherits prototype properties,
So, I have modified return key in obj; to return Object.hasOwn(obj, key);

cjyuan · 2025-12-08T01:00:55Z

Sprint-2/implement/contains.test.js

 // Then it should return false or throw an error
+
+test("Should return false when invalid parameters are used", () => {
+  expect(contains([], "a")).toEqual(false);      // array


Arrays are objects in JavaScript, and they do have property names -- just not the same ones as objects.
Which keys do arrays have, and how does that affect how reliable your test is?

When testing whether the function handles arrays properly, try using a key that an array might
realistically contain. Otherwise, you might get a passing test even if the function isn't checking for arrays at all.

Thank you @cjyuan, I have tried to include test which address that an array might realistically contain. e.g. below
expect(contains([1, 2, 3], "1")).toEqual(true); // "1" is a key
expect(contains([1, 2, 3], "3")).toEqual(false); // "3" is not a key

cjyuan · 2025-12-08T01:03:12Z

Sprint-2/implement/querystring.js

+
+      // If '=' not found we have a key exists but value is empty
+
+      paramKey = pair;


You missed decode this paramKey.

You missed decode this paramKey.

Thank you for pointing out that, I have modified it to be with added decode.

param key = decodeURIComponent(pair);

cjyuan · 2025-12-08T01:03:36Z

Sprint-2/implement/tally.js

+    return {};
+  }
+
+  const counts = {};


Does the following function call returns the value you expect?

tally(["toString", "toString"]);

Suggestion: Look up an approach to create an empty object with no inherited properties.

Does the following function call returns the value you expect?

tally(["toString", "toString"]);

Suggestion: Look up an approach to create an empty object with no inherited properties.

Thank you, I tested it and it returns {toString: 'function toString() { [native code] }11'} , as it is getting the inherent property and I have come to know that const counts = Object.create(null); solves the case.

cjyuan · 2025-12-08T01:07:38Z

Sprint-2/stretch/count-words.js

+function countWords(string) {
+  //  validation of input
+  if (typeof string !== "string") {
+    throw new Error("Input should be a string");
+  }
+  if (string === "") return {};
+  const counts = {};
+
+  // Remove punctuation and lowercase everything
+
+  const cleanText = string.replace(/[.,!?]/g, "").toLowerCase();
+  const words = cleanText.split(" ");
+
+  // Count word frequencies
+  for (const word of words) {
+    counts[word] = (counts[word] || 0) + 1;
+  }
+
+  // Sort by frequency (most common first)
+  const sorted = Object.entries(counts).sort((a, b) => b[1] - a[1]);
+
+  return Object.fromEntries(sorted);
+}
+
+console.log(countWords("Hello!, my friend, You and me, and you."));
+
+// In count-words.js function countWords implemented. 


Do the following function calls return what you expect?

countWords("constructor constructor"); countWords(" Hello World ");

Note: Change is optional as this is a stretch exercise.

Do the following function calls return what you expect?

countWords("constructor constructor"); countWords(" Hello World ");

Note: Change is optional as this is a stretch exercise.

Thank you @cjyuan, I have modified it to handle inherent property cases and remove empty strings.

const counts = Object.create(null);
const words = cleanText.split(" ").filter(Boolean);

…ients appear on new line.

…key);

cjyuan

Changes look great.

Have you run all the Jest test scripts to ensure everything works as expected after making the latest changes?

Mahtem · 2025-12-10T17:00:11Z

Changes look great.

Have you run all the Jest test scripts to ensure everything works as expected after making the latest changes?

Hello @cjyuan , yes all the jest scripts passed.

cjyuan · 2025-12-10T17:04:12Z

Sprint-2/implement/contains.test.js

+test("Should return false when invalid parameters are used", () => {
+  expect(contains([1, 2, 3], "1")).toEqual(true); // "1" is a key
+  expect(contains([1, 2, 3], "3")).toEqual(false); // "3" is not a key


The test on line 56 does not quite match the test description.

The test on line 56 does not quite match the test description.

Yes, it's right.. I have tried to make is separated as follows:

test("Should correctly detect keys in arrays", () => {
expect(contains([1, 2, 3], "1")).toEqual(true); // "1" is a key
expect(contains([1, 2, 3], "3")).toEqual(false); // "3" is not a key
});

test("Should return false when invalid parameters are used", () => {
expect(contains(null, "a")).toEqual(false); // null
expect(contains(5, "a")).toEqual(false); // number
expect(contains("hello", "a")).toEqual(false); // string

cjyuan · 2025-12-10T19:12:20Z

All good. Well done!

Mahtem · 2025-12-10T19:19:02Z

All good. Well done!

Thank you.

Mahtem added 18 commits November 25, 2025 00:22

Address.js log function corrected

13acaf4

Author.js corrected.

7f8b224

recipe.js log function corrected.

ba4ef98

contains.js function implemented and tested.

6453fe4

In contains.test.js tests for contains.test.js passed

cb4642b

In lookup.js function createLookup implemented.

9dd1769

In lookup.test.js test cases added and passed.

8bdd6c5

In querystring.js function implemented.

2c03056

In querystring.test.js test edge cases added.

1101ce6

In tally.js function tally() implemented.

d0665bd

In tally.test.js test cases added and passed.

d471bca

In invert.js invert function implemented.

e550d17

// In invert.test.js test cases tested.

218caa6

In count-words.js function countWords implemented.

d2985e4

In mode.js function calculateMode refactored.

6dff138

In mode.test.js test cases passed

0088e75

In till.js function implemented.

bd20fa1

In till.test.js test cases written and tested.

3735e91

Mahtem added Needs Review Trainee to add when requesting review. PRs without this label will not be reviewed. 📅 Sprint 2 Assigned during Sprint 2 of this module labels Dec 6, 2025

cjyuan reviewed Dec 8, 2025

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 Dec 8, 2025

Mahtem added 6 commits December 10, 2025 11:56

recipe.js modified "${recipe.ingredients.join("\n")}`) to make ingred…

2f7f0e2

…ients appear on new line.

In contains.js modified return function as return Object.hasOwn(obj, …

161b871

…key);

contains.test.js re-tested.

5cddc23

Decoding of paramKey = decodeURIComponent(pair); added.

aab642f

In tally.js modification made.

7ef1f9c

Modified to handle inherent property cases and to remove empty spaces.

ba1bc62

Mahtem added the Needs Review Trainee to add when requesting review. PRs without this label will not be reviewed. label Dec 10, 2025

cjyuan reviewed Dec 10, 2025

View reviewed changes

cjyuan removed the Needs Review Trainee to add when requesting review. PRs without this label will not be reviewed. label Dec 10, 2025

The "if (typeof obj !== "object" || obj === null)" modified.

2528d55

cjyuan reviewed Dec 10, 2025

View reviewed changes

Test case description updated

8e4807e

cjyuan added Complete Volunteer to add when work is complete and all review comments have been addressed. and removed Reviewed Volunteer to add when completing a review with trainee action still to take. labels Dec 10, 2025

Mahtem mentioned this pull request Dec 12, 2025

Manchester |Data groups | Mahtem T. Mengstu Mahtem/My-Coursework-Planner#6

Open

illicitonion closed this Jan 7, 2026


		// If '=' not found we have a key exists but value is empty

		paramKey = pair;

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Mahtem commented Dec 6, 2025

Learners, PR Template

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Mahtem commented Dec 10, 2025

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cjyuan commented Dec 10, 2025

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Mahtem commented Dec 10, 2025

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