Functors

_Functors.md

Functors

According to wikipedia a functor is a type of mapping between categories arising in category theory. To simplefy it, functors are objects, types, function that contain implementation of the map function. The map transforms contents of the functor.

What needs to be fulfilled?

• implementation of map function that transforms contents of the functor
• map always returns functors of the same type

Examples

• arrays

example1-functors.js

const itemsOnCheck = [
    {
        name: 'fries',
        price: 599,
        taxPercent: 0.1  
    }, {
        name: 'burger',
        price: 1599,
        taxPercent: 0.1  
    }, {
        name: 'coca-cola',
        price: 599,
        taxPercent: 0.2  
    }
]

// #map transformed contents of the array.
itemsOnCheck.map(item => item.price); // [ 599, 1599, 599 ]