Golang Convert a slice of structs to a map of structs: Mastering Go Application Design

sliceToMap.go

package main

import "fmt"

// sliceToMap creates a new map of type map[string]T and uses func 'f' to set the key of the new map
// from the slice
func sliceToMap[T any](items []T, f func(item T) string) map[string]T {
	itemMap := make(map[string]T, len(items))
	for _, item := range items {
		itemMap[f(item)] = item
	}
	return itemMap
}

// Example

type Item struct {
	ID    string
	Name  string
	Price int
}

type Element struct {
	Name   string
	Weight int
}

func main() {
	// Create a slice of items
	items := []Item{
		{"item1", "Item 1 Name", 100}, {"item2", "Item 2 Name", 200}, {"item3", "Item 3 Name", 300},
	}

	// Convert the slice to a map using the ID field as the key
	itemMap := sliceToMap(items, func(item Item) string {
		return item.ID
	})

	fmt.Println("itemMap:", itemMap)
	// map[item1:{item1 Item 1 Name 100} item2:{item2 Item 2 Name 200} item3:{item3 Item 3 Name 300}]

	elements := []Element{
		{"element1", 100}, {"element2", 200}, {"element3", 300},
	}

	elementMap := sliceToMap(elements, func(element Element) string {
		return element.Name
	})

	fmt.Println("elementMap:", elementMap)
	// map[element1:{element1 100} element2:{element2 200} element3:{element3 300}]

}