Merge pull request #17 from gobuffalo/feature-adding-default-helper

Adding default helper

.github/workflows/tests.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        go-version: [1.12.x, 1.13.x]
+        go-version: [1.15.x, 1.16.x]
         os: [macos-latest, windows-latest, ubuntu-latest]
     steps:
     - name: Checkout Code

content/content.go

@@ -4,14 +4,16 @@ import "github.com/gobuffalo/helpers/hctx"
 
 // Keys to be used in templates for the functions in this package.
 const (
-	OfKey  = "contentOf"
-	ForKey = "contentFor"
+	OfKey      = "contentOf"
+	ForKey     = "contentFor"
+	DefaultKey = "default"
 )
 
 // New returns a map of the helpers within this package.
 func New() hctx.Map {
 	return hctx.Map{
-		OfKey:  ContentOf,
-		ForKey: ContentFor,
+		OfKey:      ContentOf,
+		ForKey:     ContentFor,
+		DefaultKey: WithDefault,
 	}
 }

content/default.go

@@ -0,0 +1,14 @@
+package content
+
+import "github.com/gobuffalo/helpers/hctx"
+
+// WithDefault returns the key if exists, otherwise it returns
+// defaultValue passed.
+func WithDefault(key string, defaultValue interface{}, help hctx.HelperContext) interface{} {
+	value := help.Value(key)
+	if value != nil {
+		return value
+	}
+
+	return defaultValue
+}

content/default_test.go

@@ -0,0 +1,43 @@
+package content
+
+import (
+	"testing"
+
+	"github.com/gobuffalo/helpers/helptest"
+	"github.com/stretchr/testify/require"
+)
+
+func Test_Default(t *testing.T) {
+	r := require.New(t)
+	def := "notavailable"
+
+	t.Run("NotPresent", func(t *testing.T) {
+		hc := helptest.NewContext()
+		res := WithDefault("nothere", def, hc)
+		r.Equal(res, def)
+	})
+
+	t.Run("Present", func(t *testing.T) {
+		hc := helptest.NewContext()
+		hc.Set("there", "someval")
+		res := WithDefault("there", def, hc)
+		r.Equal(res, "someval")
+	})
+
+	t.Run("PresentNil", func(t *testing.T) {
+		hc := helptest.NewContext()
+		hc.Set("nil", nil)
+		res := WithDefault("nil", def, hc)
+		r.Equal(res, "notavailable")
+	})
+
+	t.Run("PresentPointer", func(t *testing.T) {
+		hc := helptest.NewContext()
+		a := "something"
+		p := &a
+		hc.Set("pointer", p)
+		res := WithDefault("pointer", def, hc)
+		r.Equal(res, p)
+		r.NotEqual(res, a)
+	})
+}