Node.js

const value = "b";

switch (value) {
  case "a":
    console.log("A");
    break;
  case "b":
    console.log("B");
    break;
  case "c":
    console.log("C");
    break;
  default:
    console.log("first default");
}

switch (value) {
  case "a":
    console.log("A - falling through");
  case "b":
    console.log("B - falling through");
  case "c":
    console.log("C - falling through");
  default:
    console.log("second default");
}

Output

B
B - falling through
C - falling through
second default

Go

package main

import "fmt"

func main() {
	value := "b"

	switch value {
	case "a":
		fmt.Println("A")
	case "b":
		fmt.Println("B")
	case "c":
		fmt.Println("C")
	default:
		fmt.Println("first default")
	}

	switch value {
	case "a":
		fmt.Println("A - falling through")
		fallthrough
	case "b":
		fmt.Println("B - falling through")
		fallthrough
	case "c":
		fmt.Println("C - falling through")
		fallthrough
	default:
		fmt.Println("second default")
	}
}

Output

B
B - falling through
C - falling through
second default