JavaScript Functions Checkpoint

A small collection of JavaScript functions grouped into three categories and rendered in a simple web page:

• String manipulation
• Array utilities
• Mathematical helpers

The page displays sample results for each function so you can quickly verify behavior in the browser.

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Project structure

.
├─ index.html      # Web page that loads and displays the results
├─ main.js         # All functions + small UI to show sample outputs
└─ style.css       # Minimal styling for cards and layout

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Functions implemented

String manipulation

• reverseString(str) → string: reverse the characters of a string.
• countCharacters(str) → number: return the number of characters.
• capitalizeWords(sentence) → string: capitalize the first letter of each word.

Array utilities

• findMaximum(arr) → number | undefined: largest value (undefined for empty arrays).
• findMinimum(arr) → number | undefined: smallest value (undefined for empty arrays).
• sumOfArray(arr) → number: sum of elements (treats array as numbers).
• filterArray(arr, condition) → Array: elements that satisfy the predicate.

Mathematical helpers

• factorial(n) → number | undefined: n! for n ≥ 0 (undefined for negative n).
• isPrime(num) → boolean: primality test with sqrt optimization.
• fibonacciSequence(terms) → number[]: sequence with given number of terms.

Edge cases handled:

• Empty arrays for min/max → undefined.
• Negative factorial input → undefined.
• Fibonacci terms <= 0 → []; terms === 1 → [0].

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How to run

You only need a browser.

1. Double‑click index.html to open it in your default browser.

   • You should see three sections (cards) with computed results.

2. Optional (recommended): use VS Code + Live Server

   • Install the "Live Server" extension.
   • Right‑click index.html → "Open with Live Server".
   • Any edits to main.js or style.css will live‑reload.

Note: This project renders results in the DOM (via the #results element), so running node main.js in a terminal won’t work because document is not available in Node.

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Try your own inputs

In main.js, scroll to the bottom where the sample cards are created and tweak the input values:

• Update the example strings passed to reverseString, countCharacters, and capitalizeWords.
• Change the numbers array to test different datasets for findMaximum, findMinimum, sumOfArray, and filterArray.
• Adjust the numbers for factorial, isPrime, and the number of terms for fibonacciSequence.

You can also reuse the functions elsewhere—each is a plain, pure function.

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Submission tips

• If you need to share a link with your instructor:
  • Create a GitHub repository, add these three files, and push.
  • Enable GitHub Pages on the repo (Settings → Pages) and pick the main branch.
  • Share the GitHub Pages URL or the repository link.
• Alternatively, compress the folder as a .zip and submit/upload per instructions.

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Notes

• Code is written in plain ES5/ES6 JavaScript, no external dependencies.
• Styling is minimal and responsive; tweak style.css as you like.
• Functions are documented inline with clear names for readability.