LONDON | GISLAINE DELLA BELLA | Module-Data-Groups | Week-2

[Della-Bella]

Learners, PR Template

Self checklist

• [X ] I have committed my files one by one, on purpose, and for a reason
• [X ] I have titled my PR with COHORT_NAME | FIRST_NAME LAST_NAME | REPO_NAME | WEEK
• [X ] I have tested my changes
• [X ] My changes follow the style guide
• [X ] My changes meet the requirements of this task

Changelist

Good evening, Volunteer,
Here are my code exercises from Week 2. I'm still finding it a little confusing, but I’m getting better at reading and explaining the code. However, I’m not completely comfortable writing everything on my own just yet.
Thank you for your time and support,
Gislaine

Questions

Ask any questions you have for your reviewer.

[cjyuan]

Code is pretty solid.

I left a few comments. I marked the more important ones with Todo .

Note: Your current branch also contains modified files in the Sprint-1 folder.

[cjyuan]

Suggestion
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( obj.hasOwnProperty(propertyName) );   // false

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

[Della-Bella]

From my search - Key Difference

• Use in if you want to check all properties, including inherited ones.
• Use hasOwnProperty if you only care about the object's own properties.

What I understood I should use “hasOwnProperty “as I want to check only on the object and not on inherited ones. But the description says I need to check using “in”. ?

Therefore chnaging the function to:

function contains(obj, property) { // Check if obj is an object (not null) and not an array if ( typeof obj === "object" && obj !== null && Object.prototype.hasOwnProperty.call(obj, property) ) { return true; // Property exists as an own property } return false; // Property doesn't exist or obj is not a valid object }

it fails when rejecting checking if t is an Array.

[cjyuan]

if (condition === true)
  return true;
else
  return false;

could be simplified as return (condition === true);

[Della-Bella]

function contains(obj, property) {
// Check if obj is an object (not null) and not an array
if (
typeof obj === "object" && obj !== null &&!Array.isArray(obj) && property in obj
) {
return (condition === true);
} else {
return false;
}
} // when I change to return (condition === true); one of my codes fail.

[cjyuan]

Todo
Can you try also expect(contains(arrayInput, "1")).toBe(false);?

[Della-Bella]

Hi Cjyuan,
I have add!Array.isArray(obj) for the arrays to be considered as aa "object".

Test Suites: 1 passed, 1 total
Tests: 5 passed, 5 total

[cjyuan]

Only one test?

[cjyuan]

Todo: Can you recheck the answers to questions (b) and (c)?

[Della-Bella]

a) What is the current return value when invert is called with { a : 1 }= return is { '1': 'a' }

b) What is the current return value when invert is called with { a: 1, b: 2 } = { '1': 'a', '2': 'b' }

c) What is the target return value when invert is called with {a : 1, b: 2} = { '1': 'a', '2': 'b' }

[cjyuan]

What do you expect from invert( { a: 1, b: 1 } )?

[Della-Bella]

This code will return true.

[cjyuan]

parseInt() can also work on the string value of coin without first removing "p" from the string. You may want to find out how parseInt() work.

[cjyuan]

Todo
For each of the following function calls, does your function return the value you expected?

parseQueryString("a=b&=&c=d")
parseQueryString("a=")
parseQueryString("=b")
parseQueryString("a=b&&c=d")
parseQueryString("a%25b=c%26d`)

Note: the %25 and %26 are URL encoded or percent encoded characters.

[Della-Bella]

Hi Cyuan,
I did make some changes but honestly, it is another level to me. I'm studying these days JS things I kow I left behind and theses tests are one of them.