Use Go Channels as Promises and Async/Await

1asyncawait.js

// Javascript.

const one = async () => {
    // Simulate a workload.
    sleep(Math.floor(Math.random() * Math.floor(2000)))
    return 1
}

const two = async () => {
    // Simulate a workload.
    sleep(Math.floor(Math.random() * Math.floor(1000)))
    sleep(Math.floor(Math.random() * Math.floor(1000)))
    return 2
}

const r = await Promise.race(one(), two())
console.log(r)

2asyncawait.go

// Go.

package main

import (
	"fmt"
	"math/rand"
	"time"
)

func one() <-chan int32 {
	r := make(chan int32)

	go func() {
		defer close(r)

		// Simulate a workload.
		time.Sleep(time.Millisecond * time.Duration(rand.Int63n(2000)))
		r <- 1
	}()

	return r
}

func two() <-chan int32 {
	r := make(chan int32)

	go func() {
		defer close(r)

		// Simulate a workload.
		time.Sleep(time.Millisecond * time.Duration(rand.Int63n(1000)))
		time.Sleep(time.Millisecond * time.Duration(rand.Int63n(1000)))
		r <- 2
	}()

	return r
}

func main() {
	var r int32
	select {
	case r = <-one():
	case r = <-two():
	}

	fmt.Println(r)
}