Go Templates: two or more slices ranges - templates

Question

The next code works perfect for output one slice inside the HomeTemplate.
main.go
type Item struct {
Id int
Name string
Type string
}
var tmpl = template.Must(template.ParseGlob("tmpl/*"))
func Index(w http.ResponseWriter, r *http.Request) {
db := database.DbConn()
selDB, err := product.ByID()
if err != nil {
panic(err.Error())
}
i := Item{}
resItems := []Item{}
for selDB.Next() {
var id int
var product_name, product_type string
err = selDB.Scan(&id, &product_name, &product_type)
if err != nil {
panic(err.Error())
}
i.Id = id
i.Name = product_name
i.Type = product_type
resItems = append(resItems, i)
}
tmpl.ExecuteTemplate(w, "HomeTemplate", resItems)
// Close database connection
defer db.Close()
}
In the template forks fine the next code:
{{ range . }}
{{ .Name }}<br />
{{ end }}
Why something like this does not work?
{{ range .resItems }}
{{ .Name }}<br />
{{ end }}
What if I want output two or more slices, what I need to do or change?
Thank you

Answer 1

first question, why rang .resItems doesn't work.
In template, . means current item. like this in java.
if . in some direction like range, it means the item from range operation.
if not, it means the item you passed form ExecuteTemplate() method. like in ExecuteTemplate(w, "HomeTemplate", resItems), . means resItems. so you can not use .resItems because it means resItems have a value called resItems.
second, if you have more slices to pass to template, you can add all of them to a map, like this:
t := template.New("test")
t, _ = t.Parse(`
test range
{{range .first}} {{.}} {{end}}
{{range .second}} {{.}} {{end}}
`)
var res = make(map[string]interface{})
aa := []string{"first", "second"}
bb := []string{"123", "456"}
res["first"] = aa
res["second"] = bb
t.Execute(os.Stdout, res)
// output
test range
first second
123 456
I have two array aa and bb, and add them to a map then pass it to the template. In template, . means the map, and .first got the array aa. and so as bb.
Hope this can help you...