feat: goctl model Add a new method hasField (#5484)

tools/goctl/util/templatex.go

@@ -15,15 +15,17 @@ const regularPerm = 0o666
 
 // DefaultTemplate is a tool to provides the text/template operations
 type DefaultTemplate struct {
-	name  string
-	text  string
-	goFmt bool
+	name    string
+	text    string
+	goFmt   bool
+	funcMap template.FuncMap
 }
 
 // With returns an instance of DefaultTemplate
 func With(name string) *DefaultTemplate {
 	return &DefaultTemplate{
-		name: name,
+		name:    name,
+		funcMap: make(template.FuncMap),
 	}
 }
 
@@ -55,7 +57,11 @@ func (t *DefaultTemplate) SaveTo(data any, path string, forceUpdate bool) error
 
 // Execute returns the codes after the template executed
 func (t *DefaultTemplate) Execute(data any) (*bytes.Buffer, error) {
-	tem, err := template.New(t.name).Parse(t.text)
+	tmp := template.New(t.name)
+	if len(t.funcMap) > 0 {
+		tmp.Funcs(t.funcMap)
+	}
+	tem, err := tmp.Parse(t.text)
 	if err != nil {
 		return nil, errorx.Wrap(err, "template parse error:", t.text)
 	}
@@ -79,6 +85,16 @@ func (t *DefaultTemplate) Execute(data any) (*bytes.Buffer, error) {
 	return buf, nil
 }
 
+// AddFunc adds a template function. It returns the template instance for chaining.
+// If funcName is empty or function is nil, it returns the template without modification.
+func (t *DefaultTemplate) AddFunc(funcName string, function any) *DefaultTemplate {
+	if funcName == "" || function == nil {
+		return t
+	}
+	t.funcMap[funcName] = function
+	return t
+}
+
 // IsTemplateVariable returns true if the text is a template variable.
 // The text must start with a dot and be a valid template.
 func IsTemplateVariable(text string) bool {