FUNCTIONAL PROGRAMMING

Functional programming is a programming paradigm style of building the structure and elements of computer programs that treats computation as the evaluation of mathematical function and avoids changing-state and mutable data. (Taken from Wkipedia).

PURE FUNCTION

• Is a function that returns the same result if given the same arguments.

• Are function that are stable, consistent and predictable.

IMPURE FUNCTION

• Is a function that uses a global object that was not passed as a parameter.

• A function that reads external file.

• A function that relies on a random number generator.

IMMUTABILITY

Its a data that is unable to be changed instead you create a new one.

PURE FUNCTION + IMMUTABLE DATA = REFERENTIAL TRANSPARENCY

HIGHER ORDER FUNCTION

• Are functions that take one more functions as arguments or return functions as a result.

  FILTER

Is a method given a collection that filters using an attribute and expectes a true or a false value to determine if the element should or should not be included in the result.

MAP

Is a method that transforms a collection by applying a function to all its elements and returns a new collection of returned values.

• Reference