London | 26-ITP-Jan | Oussama Mouggal | Sprint 1| Data-Groups

[Oussama-Mouggal]

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

I added tests and implemented code and checked code failure in order to pass the npm tests.

[cjyuan]

Code is correct and tests are well prepared.

I just have some suggestions.

[cjyuan]

Indentation is off.

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
?

---

If you have enabled "Format on save" but it is not working, it is likely that you haven't assign a formatter for JS file. This could happen if you have zero or multiple extensions that can format .js file.

If you have installed "Prettier" extension. To assign it as the formatter of JS code, you can try:

1. Use "Format document" to format the JS file. Sometimes, VSCode will ask you to choose a formatter, and you can manually select "Prettier".
2. Edit settings.json and set Prettier as the default formatter for JS.
   See: https://marketplace.visualstudio.com/items?itemName=esbenp.prettier-vscode

[Oussama-Mouggal]

Thanks for your valuable feedback.I fixed it and corrected the indentation in median.js and configured workspace VS Code settings to use Prettier as the default formatter for JavaScript with format-on-save/paste enabled.

[cjyuan]

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

[Oussama-Mouggal]

Thank you for the feedback.I updated the decimal test in Sprint-1 to use Jest’s floating-point matcher instead of exact equality.

[cjyuan]

Changes look good. Well done.