GOOS=js GOARCH=wasm go build -o main.wasm main.go

applyFilteFunc := js.FuncOf(applyFilter) //wrapper
js.Global().Set("applyFilter", applyFilteFunc)

window = js.Global()
doc = window.Get("document")
squaresCanvas = doc.Call("getElementById", "sCanvas")
sctx = squaresCanvas.Call("getContext", "2d")

wordCanvas = doc.Call("getElementById", "wCanvas")
wctx = wordCanvas.Call("getContext", "2d")

width = window.Get("innerWidth").Float()
height = window.Get("innerHeight").Float()

squaresCanvas.Set("width", width)
squaresCanvas.Set("height", height)

<div class="my-first-vugu-comp">
    <button @click="data.Toggle()">Test</button>
    <div vg-if="data.Show">I am here!</div>
</div>

<style>
.my-first-vugu-comp { background: #eee; }
</style>

<script type="application/x-go">
type RootData struct { Show bool }
func (data *RootData) Toggle() { data.Show = !data.Show }
</script>

<div class="demo">
    <div vg-if='data.isLoading'>Loading...</div>
    <div vg-if='len(data.bpi.BPI) > 0'>
        <div>Updated: <span vg-html='data.bpi.Time.Updated'></span></div>
        <ul>
            <li vg-for='data.bpi.BPI'>
                <span vg-html='key'></span> <span vg-html='fmt.Sprint(value.Symbol, value.RateFloat)'></span>
            </li>
        </ul>
    </div>
    <button @click="data.HandleClick(event)">Fetch Bitcoin Price Index</button>
</div>

<script type="application/x-go">
import "encoding/json"
import "net/http"
import "log"
type RootData struct {
    bpi bpi
    isLoading bool
}
type bpi struct {
    Time struct { Updated string `json:"updated"` } `json:"time"`
    BPI map[string]struct { Code string `json:"code"`; Symbol string  `json:"symbol"`; RateFloat float64 `json:"rate_float"` } `json:"bpi"`
}
func (data *RootData) HandleClick(event *vugu.DOMEvent) {
    data.bpi = bpi{}
    ee := event.EventEnv()
    go func() {
        ee.Lock()
        data.isLoading = true
        ee.UnlockRender()
        res, err := http.Get("https://api.coindesk.com/v1/bpi/currentprice.json")
        if err != nil {
            log.Printf("Error fetch()ing: %v", err)
            return
        }
        defer res.Body.Close()
        var newb bpi
        err = json.NewDecoder(res.Body).Decode(&newb)
        if err != nil {
            log.Printf("Error JSON decoding: %v", err)
            return
        }
        ee.Lock()
        defer ee.UnlockRender()
        data.bpi = newb
        data.isLoading = false
    }()
}
</script>