01: Node Ecosystem

Submission Instructions

• Read this document entirely and estimate how long this assignment will take.
• Work in a fork of this repository
• Work in a branch on your fork
• Write all of your code in a directory named lab- + <your name> e.g. lab-susan
• Submit on canvas a question and observation,your original estimate, how long you spent, and a link to your pull request

Configuration

Configure the root of your repository with the following files and directories. Thoughtfully name and organize any additional configuration or module files.

• README.md - contains your documentation
• .gitignore - contains a robust .gitignore file
• .eslintrc.json - contains the course linter configuration
• .eslintignore - contains the course linter ignore configuration
• lib/ - contains module definitions
• test/ - contains unit tests

Testing

Greet Module Tests

• Write a test that expects the greet module to return null when you supply non-string values
• Write a test the expects the greet module to return 'hello world'
  • This should happen when invoked with 'world' as the first argument

Arithmetic Module Tests

• Test each method for proper use (invoked with number arguments)
• Test each method for inproper use (invoked with one or more non-number arguments)

Feature Tasks

Greet Module

Create a NodeJS module in the lib directory named greet.js. This module should export a single function.

• The greet function should have a single parameter (arity of one) that should expect a string as it's input
• The greet function should return the input name, concatenated with "hello ": eg. ("hello susan")
• The greet function should return null if the input is not a string

Arithmetic Module

Create a NodeJS module in the lib directory named arithmetic.js. This module exports an object and should have add and sub methods that implement addition and subtraction.

• The add method should have a 2 parameters (airty of two)
  • if either argument is a non-number the function should return null
  • else return the sum of the 2 numbers
• The sub method should have 2 parameters (airty of two)
  • if either argument is a non-number the function should return null
  • else return the second parameter subtracted from the first parameter

Documentation

In your README.md file, describe the exported values of each module defined in your lib directory. Every function description should include it's airty (expected number of parameters), the expected data for each parameter (data-type and limitations), and the expected output behavior (for both valid and invalid use). Feel free to include any additional information that you would like.