golang_mastery_struct_vs_object_pointer

golang_mastery_struct_vs_object_pointer.go

// Copyright 2018 Lukas Lukac <https://lukaslukac.io>; All rights reserved.
// Play: https://play.golang.org/p/E34Y0SfAyK9
package main

import (
	"fmt"
)

type illusion struct {
	magicianCount int
}

func (i *illusion) increaseMagicianCount() {
	i.magicianCount++
}

func main() {
	myIllusion := &illusion{}
	myIllusion.increaseMagicianCount()

	fmt.Println(myIllusion.magicianCount) // Expected: 1, Actual: 1

	// ↟ equivalent to ↡

	myIllusion = &illusion{}
	increaseMagicianCount(myIllusion)

	fmt.Println(myIllusion.magicianCount) // Expected: 1, Actual: 1
	
	increaseMagicianCount(nil)            // I am evil developer
	fmt.Println(myIllusion.magicianCount) // Expected: 1, Actual: 1
}

func increaseMagicianCount(i *illusion) {
        // with a value receiver you don't have to add unnecessary IF conditions and worry about panic attacks because
        // is possible to receive NIL on a pointer receiver
	if i == nil {
		return
	}
	
	i.magicianCount++
}