new function one for creating file and one for only byte slice

templateBuilder.go

@@ -1,6 +1,7 @@
 package templatebuilder
 
 import (
+	"bytes"
 	"html/template"
 	"os"
 )
@@ -12,7 +13,7 @@ func NewTemplateBuilder() *TemplateBuilder {
 	return &TemplateBuilder{}
 }
 
-func (tb *TemplateBuilder) Generate(templatePath, outputFile string, data any) error {
+func (tb *TemplateBuilder) GenerateFile(templatePath, outputFile string, data any) error {
 	tmpl, err := template.ParseFiles(templatePath)
 	if err != nil {
 		return err
@@ -30,3 +31,19 @@ func (tb *TemplateBuilder) Generate(templatePath, outputFile string, data any) e
 	}
 	return nil
 }
+
+func (tb *TemplateBuilder) Generate(templatePath string, data any) (b []byte, err error) {
+	tmpl, err := template.ParseFiles(templatePath)
+	if err != nil {
+		return
+	}
+
+	var buf bytes.Buffer
+	err = tmpl.Execute(&buf, data)
+	if err != nil {
+		return
+	}
+	b = buf.Bytes()
+
+	return
+}

test/templateBuilder_test.go

@@ -11,13 +11,24 @@ type Inventory struct {
 	Count    uint
 }
 
-func TestTemplateBuilder(t *testing.T) {
-
+func TestTemplateBuilderFile(t *testing.T) {
 	sweaters := Inventory{"wool", 17}
 	t.Log("start test")
 	tmplBuilder := templatebuilder.NewTemplateBuilder()
-	err := tmplBuilder.Generate("test.tmpl", "test.txt", sweaters)
+	err := tmplBuilder.GenerateFile("test.tmpl", "test.txt", sweaters)
 	if err != nil {
 		t.Fatal(err)
 	}
 }
+
+func TestTemplateBuilderData(t *testing.T) {
+	sweaters := Inventory{"wool", 17}
+	t.Log("start test")
+	tmplBuilder := templatebuilder.NewTemplateBuilder()
+	data, err := tmplBuilder.Generate("test.tmpl", sweaters)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	t.Log(string(data))
+}