Generics

Intro

With generics, we can declare and use functions or types that are written to work with any type of a set of types provided.

Simply, your generic functions and types will work with any number of types that you define them for, hence making them more useful in a broader sense in your Go program or project as a whole.

package main

import (
    "fmt"
)

// Concats the string values of map m.
func ConcatStr(m map[string]string) string {
    var s string
    for _, v := range m {
        s += v
    }
    return s
}

// Concats the int values of map m.
func ConcatInt(m map[string]int) int {
    var s int
    for _, v := range m {
        s += v
    }
    return s
}

// Concat generic function
func ConcatGeneric[K comparable, V Concat](m map[K]V) V {
    var s V
    for _, v := range m {
        s += v
    }
    return s
}

type Concat interface {
    string | int
}

func main() {
    // Initialize a map for the int values
    map_string_int := map[string]int{
        "first":  13,
        "second": 26,
        "third":  39,
    }

    // Initialize a map for the string values
    map_string_string := map[string]string{
        "first":  "firstval",
        "second": "secondval",
        "third":  "thirdval",
    }

    // call the two functions
    fmt.Println("Concat outputs from the functions: \n",
        ConcatInt(map_string_int), "\n",
        ConcatStr(map_string_string))

    // call the generic function with two kinds of inputs
    fmt.Println("Concat with generic function: \n",
        ConcatGeneric(map_string_int), "\n",
        ConcatGeneric(map_string_string))
}

Reference: https://medium.com/this-code/understanding-golang-generics-with-examples-907cfbd5023b