learn-co-curriculum / fewpjs_rob_the_museum

Rob the Museum

Learning Goals

• Read information file data using fs.readFileSync
• Process CSV data
• Use classes to represent data retrieved from file
• Follow tests to establish criminal conspiracy

Introduction

In this lab, you are a notorious art thief. Your goal is to "case" the museum and establish critical information about the crime that you are about to commit.

IMPORTANT NOTE: Obviously, we do not support robbing museums and want to discourage you from a life of international art theft. The practical consequences and risks associated with such are covered by Donna Tartt in her book The Goldfinch.

Read Information File Data Using fs.readFileSync

JavaScript likes to work asynchronously. We saw this earlier in sending server calls with AJAX. In JavaScript, things don't always happen in the top-down reading order of the code. They happen in a mysterious "later," when the asynchronous action says "Hey, I'm done!" At a technical level, we usually say "When the asynchronous code resolves." While it's a bit strange when starting to learn programming in JavaScript in the browser, with enough labs and lessons, most students come to accept and "get it."

But when JavaScript came to the CLI environment in NodeJS, that desire for asynchronous methods remained. And, as a result, NodeJS wants to use an asynchronous design...for reading files. This is great for if your Node application needs to read in a huge file (maybe a mouse genome?). The asynchronous model will help your computer stay efficient (great!). There's definitely a time and place for needing to use the asynchronous methods for reading text files in NodeJS.

However, for simple text files this is unnecessary complexity and the designers of NodeJS recognized that. NodeJS has provided us both an asynchronous and synchronous version of reading a file. For this lesson, we're going to use the blocking, synchronous version: readFileSync.

CRITICAL THINKING: Some people consider asynchronous file reading is one of the best reasons to not learn JavaScript as your first programming language: when your first language requires you to learn about challenging concepts such as asynchrony before you can read a file, maybe you're not using the most beginner-friendly language.

We can read in a file synchronously like so:

fs.readFileSync(file-name, "utf-8")

This code will read in the contents of file-name and return a loooong String of the file-name's contents. The second argument, 'utf-8', tells NodeJS to convert the raw bits of data in the file into text format. If you do not add this argument, you'll get an Array of raw bytes versus a String.

Try using fs.readFileSync to read in a text file and assign it to a variable. Log that variable out to verify that you can read and print text files. What happens if you try the same step without the "utf-8" argument?

Rob the Museum

To start gathering information about your upcoming art heist, you will need to process the data from the art_heist.csv spreadsheet.

The basic strategy is:

1. Read in the looong String from the file
2. Use JavaScript methods to split the file's content into lines
3. Process each line to create instances of classes to help you manage complex relationships

Each row in the text file has the format:

catalogNumber,gallery name,work name, artist name, value

Each line suggests the creation of a Work with a value, a Gallery, an Artist. However, new instances should not be recreated if they already exist. If we've seen the "Blue" gallery once, we shouldn't create another "Blue" gallery, we should use the existing one.

Look at the CSV file and formulate a strategy for your program. We'll get you started in the next section.

The Museum Class

The Museum instance should keep track of the collections of works, galleries, and artists. When it is initialized, it should be given a name (name of the museum!) and a path to a CSV file to read in.

the_met = new Museum("The Metropolitan Museum of Art of New York City", "art_heist.csv")

The CSV file will then need to be prepared as you see fit. In the end, however, the Museum class must answer these questions:

• Which gallery has the most paintings (example: the_met.biggestGallery())?
• Which gallery has the fewest (example: the_met.smallestGallery())?
• Which artist has the most paintings in the museum (example: the_met.artistMostOccurring())?
• What is the total value of all the paintings of any given artist in the museum (example: the_met.valueOfArtist(artistName))?
• If we could steal all the paintings in one gallery to sell for money, which would immorally enrich us the most (example: the_met.biggestPayday())?

Conclusion

Now you are all ready to rob the museum!