FUNCTIONAL PROGRAMMING

Concepts

• What is functional programming?
  • A style of building the structure and elements of a program that treats computation as the evaluatoin of mathematical functions and avoids changing-state and mutable data
• What is a pure function and how do we know if something is a pure function?
  • it returns the same result if given the same arguments
  • it does not cause observable side effects
  • doesn’t read external files
  • doesn’t rely upon a random number generator
• What are the benefits of a pure function?
  • easire to test
• What is immutability?
  • data whose state cannot be changed after creation
• What is Referential transparency?
  • purse functions + immutable data = referential transparency

Modules and require()

• What is a module?
  • splits code up into different moduoes for different bits of code according to their funcitonality
  • essentially, just another .js file
• What does the word ‘require’ do?
  • finds a JS file, reads it, executes it, and returns the export object
• How do we bring another module into the file the we are working in?
  • declare a variable which = require([name of the module to be imported])
• What do we have to do to make a module available?
  • module.exports = [name of the module we want to export]