Hash Map structure in Go. Link: https://goplay.space/#2XYw1W3ddUf

hash.go

package main

import (
	"errors"
	"fmt"
)

type hash struct {
	vector   []interface{}
	length   int
	capacity int
}

type Hash interface {
	Insert(string, interface{}) error
	Search(string) interface{}
	Remove(string) error
	Print()
}

func NewHash(capacity int) Hash {
	h := &hash{
		vector:   make([]interface{}, capacity, capacity),
		length:   0,
		capacity: capacity,
	}

	return h
}

func (h *hash) hash(key string) int {
	var index int

	for _, rune := range key {
		index += int(rune)
	}

	return index % h.capacity
}

func (h *hash) Insert(key string, value interface{}) error {
	index := h.hash(key)

	if h.vector[index] != nil {
		return errors.New("Key already in use")
	}

	h.vector[index] = value

	return nil
}

func (h *hash) Search(key string) interface{} {
	index := h.hash(key)

	return h.vector[index]
}

func (h *hash) Remove(key string) error {
	index := h.hash(key)

	if h.vector[index] == nil {
		return errors.New("Key is not in use")
	}

	h.vector[index] = nil

	return nil
}

func (h *hash) Print() {
	for index, element := range h.vector {
		if element == nil {
			continue
		}

		fmt.Printf("%d -> %v\n", index, element)
	}
}

func main() {
	type Person struct {
		name      string
		cellphone string
	}

	NewPerson := func(name, cellphone string) *Person {
		return &Person{
			name, cellphone,
		}
	}

	hash := NewHash(500)
	hash.Print()
	fmt.Println("")

	var person *Person
	var err error

	person = NewPerson("Gerardo", "4611021234")
	err = hash.Insert(person.cellphone, person)
	fmt.Println(err)
	hash.Print()
	fmt.Println()

	person = NewPerson("Victor", "331204855")
	err = hash.Insert(person.cellphone, person)
	fmt.Println(err)
	hash.Print()
	fmt.Println()

	p := hash.Search(person.cellphone)
	fmt.Println(p)
	fmt.Println()

	err = hash.Remove(person.cellphone)
	fmt.Println(err)
	hash.Print()
	fmt.Println()

	person = NewPerson("Miguel", "331401855")
	err = hash.Insert(person.cellphone, person)
	fmt.Println(err)
	hash.Print()
	fmt.Println()

	person = NewPerson("Existing", "331401855")
	err = hash.Insert(person.cellphone, person)
	fmt.Println(err)
	hash.Print()
	fmt.Println()

}