London | 26-ITP-May | Alex Jamshidi | Sprint 2 | Exercises by Alex-Jamshidi · Pull Request #1226 · CodeYourFuture/Module-Data-Groups

Alex-Jamshidi · 2026-05-13T03:04:16Z

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

Completed exercises for Sprint 2

cjyuan

Some of the code is not consistently formatted or indented.

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 · 2026-05-13T13:21:10Z

 };

-console.log(`My house number is ${address[0]}`);
+console.log(`My house number is ${address.street}, ${address.city}, ${address.country}, ${address.postcode}`);


Your code outputs every parts of an address except the "house number".

Added house number.

I had installed prettier and enabled the formatting, however it wasn't working because I hadn't set as my default formatter. I have formatted this code now. (and gone back through all my old PRs and formatted too!)

thanks :)

cjyuan · 2026-05-13T13:25:42Z

+    if (typeof object !== 'object' || Array.isArray(object)) {return false;}
+    if (typeof property !== 'string') {return false;}


Line 2 cannot yet reject null.

updated to reject null

written tests to confirm

cjyuan · 2026-05-13T13:31:17Z

+it("given invalid parameter (an array) returns false or throws an error", () => {
+    const object = [];
+    const property = [];
+    expect(contains(object, property)).toEqual(false)


Your function can correctly return false when the first argument is an array.

However, we write tests not only to verify our current implementation, but also to ensure that future changes do not alter the function's expected behavior.

The current test cannot yet confirm the function can correctly return false when the first argument is an array
because contains([], []) could also return false simply because [] is not a key of the array.

Arrays are objects, with their indices acting as keys. A proper test should use a non-empty array along with a valid key to ensure the function returns false specifically because the input is an array, not because the key is missing.

Thanks for this, I understand.

I wrote several tests to cover all options for arrays (filled or empty).

cjyuan · 2026-05-13T13:33:10Z

-  // implementation here
+function createLookup(arrayOfArrays) {
+  const lookup = {}
+  for (array of arrayOfArrays) {


array not yet declared.

thanks, have declared with const

cjyuan · 2026-05-13T13:35:51Z

+// currently without adding this database, an unknown PEC could cause the code to get stuck in an infinite loop
+
+function changePEC(string) {
+  const PEC = {"%24": "$", "%2F": "/"}


There are more than two percentage encoded characters.

Consider using the built-in function to decode PEC's in the string instead.

I didn't know there was a function for this facepalm
I have updated to use the function, it was a lot easier :)

Thanks

cjyuan · 2026-05-13T13:39:10Z

+    const [key, value] = [pair.slice(0, index), pair.slice(index + 1)]
    queryParams[key] = value;
+    }
+    else {};


Why leave a do-nothing else block in the function?

It's a good question that doesn't have a good answer, I have removed it.

Thanks

cjyuan · 2026-05-13T13:40:50Z

+    tally = {}
+    array.forEach((item) =>{
+        if (item in tally) {tally[item] += 1}
+        else tally[item] = 1;
+    })
+    return tally


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, or

use Object.hasOwn()

that was a tough one

Wrote test for case and updated code to pass

…lookup

Alex Jamshidi added 11 commits May 13, 2026 00:58

debugged address.js

bd846e8

debugged author.js

dc61f91

debugged recipe.js

5761063

contains.test.js tests written

3ff26b1

added solution to contains.js

59b7763

written test for lookup.test.js

40a2e86

added solution to lookup.js

5567875

added solution to tally.js

f928482

completed querystring.js

3b91514

completed invert.js

352aef9

changes added that weren't saved to last commit

66a4554

Alex-Jamshidi added 📅 Sprint 2 Assigned during Sprint 2 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 May 13, 2026

This was referenced May 13, 2026

ITP May 2026 | Data Groups | Alex Jamshidi Alex-Jamshidi/My-Coursework-Planner#67

Open

Complete sprint 2 exercises Alex-Jamshidi/My-Coursework-Planner#75

Open

cjyuan reviewed May 13, 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 May 13, 2026

Alex Jamshidi added 4 commits May 13, 2026 17:28

added tests to ensure contains does not allow arrays and null, fixed …

6cb0fe2

…lookup

remove erroneous 'else'

193230c

updated code to use decodeURIcomponent

8427bfd

updated tally for edge case toString

c698639

		if (typeof object !== 'object' \|\| Array.isArray(object)) {return false;}
		if (typeof property !== 'string') {return false;}

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Alex-Jamshidi commented May 13, 2026

Learners, PR Template

Changelist

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