func main() {
    // 定义函数映射
    funcMap := template.FuncMap{
        "formatDate": func(t time.Time) string {
            return t.Format("2006-01-02")
        },
        "upper": strings.ToUpper,
        "add": func(a, b int) int {
            return a + b
        },
    }
<pre class='brush:php;toolbar:false;'>tmpl := template.New("demo").Funcs(funcMap)
tmpl, _ = tmpl.Parse("发布于：{{ formatDate .CreatedAt }}，标题：{{ upper .Title }}，总数：{{ add 1 2 }}")

data := struct {
    CreatedAt time.Time
    Title     string
}{
    CreatedAt: time.Now(),
    Title:     "golang模板实战",
}

tmpl.Execute(os.Stdout, data)

}

"formatTime": func(t time.Time, layout string) string {
    if layout == "" {
        layout = "2006-01-02 15:04:05"
    }
    return t.Format(layout)
},

"truncate": func(s string, length int) string {
    if len([]rune(s)) <= length {
        return s
    }
    return string([]rune(s)[:length]) + "..."
},

"eqAny": func(val interface{}, args ...interface{}) bool {
    for _, arg := range args {
        if val == arg {
            return true
        }
    }
    return false
},

"mul": func(a, b int) int { return a * b },
"sub": func(a, b int) int { return a - b },

"highlight": func(keyword, text string) template.HTML {
    replaced := strings.ReplaceAll(text, keyword, "<mark>"+keyword+"</mark>")
    return template.HTML(replaced)
},

// funcs/common.go
package funcs
<p>import (
"strings"
"time"
"text/template"
)</p><p>func Common() template.FuncMap {
return template.FuncMap{
"upper":   strings.ToUpper,
"lower":   strings.ToLower,
"now":     time.Now,
"format":  func(t time.Time) string { return t.Format("2006-01-02") },
}
}</p>

tmpl := template.New("").
    Funcs(funcs.Common()).
    ParseFiles("index.html")