Test golang bookmarks SDK

main.go

package main

import (
	"fmt"

	"encoding/json"

	"github.com/slack-go/slack"
)

const TOKEN = "<YOUR_TOKEN_HERE>"
const bookmark = "YOUR_BOOKMARK"
const channelID = "YOUR_CHANNEL"

func main() {
	api := slack.New(TOKEN)

	smile := ":smile:"
	empty := ""

	testEmoji(api, &smile)
	testEmoji(api, nil)
	testEmoji(api, &empty)
}

func testEmoji(api *slack.Client, emoji *string) {
	fmt.Printf("Emoji: %#v\n", emoji)
	if emoji != nil {
		fmt.Printf("%#v\n", *emoji)
	}
	params := slack.EditBookmarkParameters{
		Emoji: emoji,
	}
	bk, err := api.EditBookmark(channelID, bookmark, params)
	if err != nil {
		panic(err)
	}
	fmt.Println(prettyStruct(bk))
}

func prettyStruct(data interface{}) string {
	val, err := json.MarshalIndent(data, "", "    ")
	if err != nil {
		panic(err)
	}
	return string(val)
}

output.txt

slack % go run github.com/slack-go/slack/cmd
Emoji: (*string)(0x14000112d80)
":smile:"
{
    "id": "Bk037M7FKNKZ",
    "channel_id": "C038EDJ6HDX",
    "title": "example",
    "link": "https://example.com",
    "emoji": ":smile:",
    "icon_url": "",
    "type": "link",
    "date_created": 1647925554,
    "date_updated": 1647928061,
    "rank": "U",
    "last_updated_by_user_id": "U0381QYN0KC",
    "last_updated_by_team_id": "T6H5AR4QY",
    "shortcut_id": "",
    "entity_id": "",
    "app_id": ""
}
Emoji: (*string)(nil)
{
    "id": "Bk037M7FKNKZ",
    "channel_id": "C038EDJ6HDX",
    "title": "example",
    "link": "https://example.com",
    "emoji": ":smile:",
    "icon_url": "",
    "type": "link",
    "date_created": 1647925554,
    "date_updated": 1647928061,
    "rank": "U",
    "last_updated_by_user_id": "U0381QYN0KC",
    "last_updated_by_team_id": "T6H5AR4QY",
    "shortcut_id": "",
    "entity_id": "",
    "app_id": ""
}
Emoji: (*string)(0x14000112d90)
""
{
    "id": "Bk037M7FKNKZ",
    "channel_id": "C038EDJ6HDX",
    "title": "example",
    "link": "https://example.com",
    "emoji": "",
    "icon_url": "",
    "type": "link",
    "date_created": 1647925554,
    "date_updated": 1647928062,
    "rank": "U",
    "last_updated_by_user_id": "U0381QYN0KC",
    "last_updated_by_team_id": "T6H5AR4QY",
    "shortcut_id": "",
    "entity_id": "",
    "app_id": ""
}