Due: January 26th, 2023

Welcome to week two of CMPSC 297. In the last week we wrote some basic JavaScript to run in the browser, and installed Node.JS. This week, we'll actually use Node.JS.

This is the first week where we'll have a bit of "recommended" reading. It's not required, but we highly recommend that you read through the two markdown files in the ./reading folder. They take you through a bit of the history of JavaScript, Node, and some important syntax on JavaScript (some of which will be valuable for this week's homework!)

The project is more or less set up for you, though I'll detail how one creates a Node.JS project and runs it.

Assuming you already have Node.JS installed in your favorite editors, the way one sets up a Node.JS project is simple. Pick a folder, initialize NPM, and then run it.

Simply create a project folder, where you'll keep your project. Then, in a command line for that folder, type:

$ npm init

The command line will ask you to fill in some information. You don't need to, and can simply spam the enter key until it stops. A package.json file will be created for you within your folder.

Not a lot is valuable here, but there's a couple of important lines:

{
    ...
    "main": "index.js",
    "scripts": {
        ...
    },
    ...
    "dependencies": {
        ...
    }
}

As this is a JSON file, the ordering of things does not matter. Importantly, dependencies will get updated as we install packages (other people's code that we can use to speed up our own programming). The "main" tag should point to our entry file, or the code file that runs first when we try to run our project.

We'll call our entry file index.js. Create one in the same folder as package.json.

We can simply write out the following code:

// In ./index.js

console.log("Hello, World!");

This is the same exact syntax as before. How do we run it?

We can write, in the command line, node index.js. We can also set up an NPM script to do it, back in our ./package.json file:

{
    ...
    "scripts": {
        "start": "node --harmony index.js"
    }
    ...
}

Then, in the command line, we can type npm start. Your command line should print out "Hello, World!"

Each of the individual files represents a different deliverable. As such, you'll be working with the JavaScript files in the ./src/ directory, and importing them to the index and running them.

The ./index.js file will contain a bit of tester code for you. The command line should print out a score that you'll receive on the homework, so all you have to do is implement the functions within the ./src/ files. How convenient!

The way this is done is via node modules. Basically, each code file has a function that's exported via the module.exports keyword, and this export can be consumed in the index.js file. You can see how it's implemented in the files provided.

Implement the function fibonacci(num) that, given the number input num, returns the list of the first num fibonacci numbers.

If any errors in the input are there, return false.

Optionally, if you want to challenge yourself, try to do it in a recursive way!

Given an RGB value (as a list of numbers), convert it to HSV and return a list of three hue, saturation, and value numbers. We recommend using the following library via NPM: rgb-hsv.

Simply install it via npm install rgb-hsv. Then, implement it like the example.

Given a dictionary and a lookup item, return the value within the dictionary at the lookup. If the item doesn't exist, return False.

Similar to HW1, you'll be graded on having all of the JS files as instructed, as well as the correctness of the JS files. If your command line prints out a 100/100, then you'll get that score, or something extremely close to it.

The tests we'll run are different from your tests, so if you pass the current tests, you should be fine. However, if you write your code such that they'll only pass the tests given, then you might lose points. We strongly encourage you add your own tests (similar to how they're done in ./index.js).

Make sure your files are within the same folders that we have them.