West Midlands | 25 Sep ITP | Iswat Bello | Sprint 2 | Module Data Groups Coursework #856

Iswanna · 2025-11-16T19:47:20Z

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

This pull request includes modifications to three directories:

Debug directory: I identified and fixed bugs in each file within the debug section by first predicting the issue, then running the code with Node to confirm the behaviour. All implementations were corrected so that they now pass the associated test cases.

Implement directory: I implemented functions based on the given requirements and ensured they work across a variety of inputs. I followed the recommended order (contains → lookup → tally → querystring) and created or updated corresponding test cases for each.

Interpret directory: I interpreted larger programs with unfamiliar syntax or operators using documentation and console logging. I refactored the implementations for clarity and reliability while ensuring all existing tests continued to pass.

Questions

Hi. Please could you review my PR? I’d really appreciate your feedback.

…for...of

… line

…alid inputs

- returns true if object has property - returns false if property missing or object empty - throws TypeError for invalid inputs

…ehaves correctly

… object

… correctly

…nd invalid input

…nput

…orrect output

…ect; import invert with require

…ed by another file

… and nested object input

cjyuan

Great work! Comprehensive tests!

I only have a few suggestions.

cjyuan · 2025-11-21T11:49:44Z

Sprint-2/implement/tally.js

+    throw new TypeError("Invalid input: Input must be an array");
+  }
+
+  const result = {};


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.

No, it did not return the expected value.
expected value: {"toString": 2}
actual value: "toString": "function toString() { [native code] }11".

I would look up an approach to create an empty object with no inherited properties.

cjyuan · 2025-11-21T11:51:56Z

Sprint-2/implement/querystring.js

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


In real query string, both key and value are percent-encoded or URL encoded.
For example,

tags%5B%5D=hello%20world -> key is tags[], value is hello world

Can your function handle URL-encoded query string?

Suggestion: Look up "How to decode a URL-encoded string in JavaScript".

cjyuan · 2025-11-21T11:57:06Z

Sprint-2/implement/contains.test.js

+  expect(() => contains("hello", "location")).toThrow(
+    new TypeError("Invalid input: obj must be a plain object")
+  );
+  expect(() => contains(null, "a")).toThrow(
+    new TypeError("Invalid input: obj must be a plain object")
+  );
+  expect(() => contains(undefined, "a")).toThrow(
+    new TypeError("Invalid input: obj must be a plain object")
+  );
+  expect(() => contains(123, "a")).toThrow(
+    new TypeError("Invalid input: obj must be a plain object")
+  );
+  expect(() => contains(true, "a")).toThrow(
+    new TypeError("Invalid input: obj must be a plain object")
+  );
+  expect(() => contains([], "a")).toThrow(
+    new TypeError("Invalid input: obj must be a plain object")
+  );
+  expect(() => contains(() => {}, "a")).toThrow(
+    new TypeError("Invalid input: obj must be a plain object")
+  );


All these tests expect the same error to be thrown.
You could explore using Jest '.each' or similar approach to reduce redundant code.

I have refactored the test and pushed the changes to the remote repo

cjyuan · 2025-11-21T11:58:49Z

Sprint-2/debug/recipe.js

+for (const ingredient of recipe.ingredients) {
+  console.log(ingredient);
+}


You may also like Array.prototype.join().

I have updated the code to use Array.prototype.join() instead of the loop I used before.

Iswanna · 2025-11-21T17:49:32Z

Great work! Comprehensive tests!

I only have a few suggestions.

Thank you very much.

…oString affecting expected results

…ithout prototype conflicts

…al characters

… inputs

…console.log

cjyuan

Other changes look good.

cjyuan · 2025-11-21T19:20:15Z

Sprint-2/implement/querystring.js

+
+  if (decodeURI(queryString) === decodeURIComponent(queryString)) {
+    queryString = decodeURIComponent(queryString);
+  }
+


There may be special characters such as = and & encoded in the keys or values. If you decode the entire query string at this point, the = and & that are part of some keys or values will be mistaken for separators.

Thank you for the feedback. I have fixed the code to decode after splitting.

… and throw descriptive error for invalid URL encoding

cjyuan · 2025-11-21T20:18:47Z

Great work!

Iswanna · 2025-11-21T20:22:21Z

Great work!

Thank you so much @cjyuan for reviewing my pull request and providing detailed feedback.

Iswanna added 24 commits November 10, 2025 17:42

Predict and explain the code output; fix code where needed

745ed77

Predict and explain the output, and modify the loop from for...in to …

b63e8a8

…for...of

Predict output and fix code to display each ingredient value on a new…

554168f

… line

Add 'Answer:' clarification comments for code behavior

cf6dae4

Add test cases for 'contains' function covering valid, empty, and inv…

0601e1a

…alid inputs

Implement 'contains' function:

d5f1bae

- returns true if object has property - returns false if property missing or object empty - throws TypeError for invalid inputs

Add additional tests to each scenario to verify 'contains' function b…

fbc10ec

…ehaves correctly

Fix indentation inconsistencies in 'contains' function

70dc26c

Remove .todo and add unit test for createLookup function

829f63d

Implement createLookup function to convert array of pairs into lookup…

0ffc147

… object

Fix parseQueryString so key-value pairs with '=' in values are parsed…

99df5b6

… correctly

Fix parseQueryString to throw TypeError for non-string input

60f6d21

Add test cases covering edge cases for parseQueryString

7bb2074

Add test cases for tally function to cover empty input, duplicates, a…

a2efcdf

…nd invalid input

Add function implementation to count array items and handle invalid i…

156dfd9

…nput

Add answers to questions and fix invert() implementation to produce c…

1a47dc3

…orrect output

Add test file for invert and test that empty object returns empty obj…

9f60b8b

…ect; import invert with require

Add the module.exports statement so the invert function can be import…

acf14dd

…ed by another file

Add test to verify invert returns an empty object for empty input

92e7434

Add test to verify invert correctly swaps a single key-value pair

7ab4f2d

Add test to verify invert swaps multiple key-value pairs

c2f3fd2

Add test to verify invert throws a TypeError when given invalid input

a6a37dc

Fix invert to throw an error for non-plain object input

abaa0f8

Add additional tests for empty, single, and multiple key-value pairs,…

bcdb270

… and nested object input

Iswanna 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 Nov 16, 2025

cjyuan reviewed Nov 21, 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 Nov 21, 2025

Iswanna added 6 commits November 21, 2025 18:12

Use Object.create(null) in tally to avoid inherited properties like t…

399fbc8

…oString affecting expected results

Add test case demonstrating tally must handle items like "toString" w…

3685652

…ithout prototype conflicts

Add conditional decode step for safely handling encoded query strings

5fcad91

Add tests to ensure parseQueryString handles encoded spaces and speci…

224597c

…al characters

Refactor contains test to remove repetition using a loop over invalid…

3578991

… inputs

Replace loop with Array.prototype.join() to print ingredients in one …

0f518e2

…console.log

Iswanna added Needs Review Trainee to add when requesting review. PRs without this label will not be reviewed. and removed Reviewed Volunteer to add when completing a review with trainee action still to take. labels Nov 21, 2025

Iswanna requested a review from cjyuan November 21, 2025 19:11

cjyuan reviewed Nov 21, 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 Nov 21, 2025

Fix parseQueryString to decode keys and values safely after splitting…

3f29b47

… and throw descriptive error for invalid URL encoding

Iswanna added Needs Review Trainee to add when requesting review. PRs without this label will not be reviewed. and removed Reviewed Volunteer to add when completing a review with trainee action still to take. labels Nov 21, 2025

Iswanna requested a review from cjyuan November 21, 2025 19:55

cjyuan added Complete Volunteer to add when work is complete and all review comments have been addressed. and removed Needs Review Trainee to add when requesting review. PRs without this label will not be reviewed. labels Nov 21, 2025

Iswanna closed this Nov 21, 2025

Iswanna reopened this Nov 21, 2025

Iswanna mentioned this pull request Nov 24, 2025

West Midlands | Data groups | Iswat Bello Iswanna/My-Coursework-Planner#109

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illicitonion closed this Jan 7, 2026

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West Midlands | 25 Sep ITP | Iswat Bello | Sprint 2 | Module Data Groups Coursework #856

West Midlands | 25 Sep ITP | Iswat Bello | Sprint 2 | Module Data Groups Coursework #856

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Iswanna commented Nov 16, 2025

Learners, PR Template

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Iswanna commented Nov 21, 2025

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cjyuan commented Nov 21, 2025

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Iswanna commented Nov 21, 2025

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