lets-get-functional

An exercise in problem solving in the functional idiom.

Step 0 - Release lodown

• If you haven't release your lodown library to npm (node package manager), follow the steps in this video to do so:

  publishing-npm-packages

Step 1 - Setup

• Run os install to install Lets Get Functional
• Copy the name of your lodownpackage. It should be something like lodown-oliviasaborush
• In your bash terminal run the command npm install --global lodown-oliviasaborush with your lodown package
• In your bash terminal run the command npm link lodown-oliviasaborush with your lodown package
  • These commands will not work unless you use your lodown name
• Open index.js
• Update line 6 of index.js to reference your lodown library
• It should look something like this:

const _ = require('lodown-oliviasaborush');

Step 2 - Solve

• Implement the functions outlined below, using your lodown library
• Code and test your solutions in index.js
• Data is available to you in an Array stored in the variable customers
• To test your solutions run npm start --prefix ./<YOUR_GITHUB_FOLDER/projects/let-s-get-functional in your terminal

IMPORTANT: Make sure you replace <YOUR_GITHUB_FOLDER with your actual github folder in your workspace.

1: maleCount

• Objective: Find the number of male customers
• Input: Array
• Output: Number
• Constraints: use filter

2: femaleCount

• Objective: Find the number of female customers
• Input: Array
• Output: Number
• Constraints: use reduce

3: oldestCustomer

• Objective: Find the oldest customer's name
• Input: Array
• Output: String
• Constraints:

4: youngestCustomer

• Objective: Find the youngest customer's name
• Input: Array
• Output: String
• Constraints:

5: averageBalance

• Objective: Find the average balance of all customers
• Input: Array
• Output: Number
• Constraints:

6: firstLetterCount

• Objective: Find how many customer's names begin with a given letter
• Input: Array, Letter
• Output: Number
• Constraints:

7: friendFirstLetterCount

• Objective: Find how many friends of a given customer have names that start with a given letter
• Input: Array, Customer, Letter
• Output: Number
• Constraints:

8: friendsCount

• Objective: Find the customers' names that have a given customer's name in their friends list
• Input: Array, Name
• Output: Array
• Constraints:

9: topThreeTags

• Objective: Find the three most common tags among all customers' associated tags
• Input: Array
• Output: Array
• Constraints:

10: genderCount

• Objective: Create a summary of genders, the output should be:

{
    male: 3,
    female: 4,
    non-binary: 1
}

• Input: Array
• Output: Object
• Constraints: Use reduce

Step 3: Submit

• When you are passing all tests, run os submit
• Select your current session
• Select Let's Get Functional
• If you pass all tests, you will get a green light!