FUNCTIONAL PROGRAMMING

What is functional programming ?

Functional programming is a programming paradigm — a style of building the structure and elements of computer programs — that treats computation as the evaluation 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 ?

So how do we know if a function is pure or not? Here is a very strict definition of purity:

• It returns the same result if given the same arguments (it is also referred as deterministic)

• It does not cause any observable side effects

• It returns the same result if given the same arguments.

• What are the benefits of a pure function?

• Immediatly testable.
• Easier maintaining, refactoring, and testing.

• No need for mocking anything.

• What is immutability?

Immutability means that it can’t be changed (unchangeable)

• What is Referential transparency*? source

Referential transparency and referential opacity are properties of parts of computer programs. An expression is called referentially transparent if it can be replaced with its corresponding value (and vice-versa) without changing the program’s behavior. (pure + immutability = referential transparency)

Node JS: Modules and require()

1. What is a module?

Modules in Node.js are a set of functionalities that can be called whenever are needed.

• What does the word ‘require’ do?

It imports the data from a module, given it’s path.

• How do we bring another module into the file the we are working in?

We can do that by using the word require and give it the path of the module.

• What do we have to do to make a module available?

We can fo that by using module.exports = what ever we want to make available. Like that we can export the data which we want to make available.