Learning Functional Programming in Go

Map function

Let's create a Map function to transform the contents of a Collection.

First, let's define Object to be the empty interface type and create a Collection type to be a slice of objects:

package mainimport "fmt"type Object interface{}type Collection []Objectfunc NewCollection(size int) Collection {     return make(Collection, size)}

The NewCollection function creates a new instance of the collection with the given size:

type Callback func(current, currentKey, src Object) Object

The Callback type is a first-class function type that returns the calculated result:

func Map(c Collection, cb Callback) Collection {     if c == nil {          return Collection{}     } else if cb == nil {          return c     }     result := NewCollection(len(c)) for index, val := range c ...