From cde62528d07a6196ba683a34a1d048e2da8aa205 Mon Sep 17 00:00:00 2001
From: Chase Fleming <1666730+chasefleming@users.noreply.github.com>
Date: Wed, 22 Nov 2023 07:12:19 -0800
Subject: [PATCH 1/2] Add None Node for Noop Rendering
---
elem.go | 13 +++++++++++++
elements.go | 5 +++++
elements_test.go | 13 +++++++++++++
utils_test.go | 10 ++++++++++
4 files changed, 41 insertions(+)
diff --git a/elem.go b/elem.go
index a1ce79d..75ac219 100644
--- a/elem.go
+++ b/elem.go
@@ -58,6 +58,19 @@ type Node interface {
Render() string
}
+// NoneNode represents a node that renders nothing.
+type NoneNode struct{}
+
+// RenderTo for NoneNode does nothing.
+func (n NoneNode) RenderTo(builder *strings.Builder) {
+ // Intentionally left blank to render nothing
+}
+
+// Render for NoneNode returns an empty string.
+func (n NoneNode) Render() string {
+ return ""
+}
+
type TextNode string
func (t TextNode) RenderTo(builder *strings.Builder) {
diff --git a/elements.go b/elements.go
index b4db73a..69f9fe9 100644
--- a/elements.go
+++ b/elements.go
@@ -399,6 +399,11 @@ func Source(attrs attrs.Props, children ...Node) *Element {
// ========== Other ==========
+// None creates a NoneNode, representing a no-operation in rendering.
+func None() NoneNode {
+ return NoneNode{}
+}
+
// Raw takes html content and returns a RawNode.
func Raw(html string) RawNode {
return RawNode(html)
diff --git a/elements_test.go b/elements_test.go
index 1ea166c..bb88db8 100644
--- a/elements_test.go
+++ b/elements_test.go
@@ -509,6 +509,19 @@ func TestVideoWithSourceElementsAndFallbackText(t *testing.T) {
// ========== Other ==========
+func TestNone(t *testing.T) {
+ el := None()
+ expected := ""
+
+ assert.Equal(t, expected, el.Render(), "None should render an empty string")
+}
+
+func TestNoneInDiv(t *testing.T) {
+ expected := ``
+ actual := Div(nil, None()).Render()
+ assert.Equal(t, expected, actual)
+}
+
func TestRaw(t *testing.T) {
rawHTML := ``
el := Raw(rawHTML)
diff --git a/utils_test.go b/utils_test.go
index aaf6007..ce281d3 100644
--- a/utils_test.go
+++ b/utils_test.go
@@ -17,6 +17,16 @@ func TestIf(t *testing.T) {
assert.Equal(t, falseElement.Render(), resultFalse.Render())
}
+func TestIfUsingNone(t *testing.T) {
+ trueElement := Div(nil, Text("True Condition"))
+
+ resultWithNone := If[Node](true, trueElement, None())
+ assert.Equal(t, trueElement.Render(), resultWithNone.Render(), "If should render the true element when the condition is true")
+
+ resultWithNoneFalse := If[Node](false, trueElement, None())
+ assert.Equal(t, "", resultWithNoneFalse.Render(), "If should render nothing (empty string) when the condition is false and None is used")
+}
+
func TestTransformEach(t *testing.T) {
items := []string{"Item 1", "Item 2", "Item 3"}
From fd002e38106339d0222462a4991dc746b314d451 Mon Sep 17 00:00:00 2001
From: Chase Fleming <1666730+chasefleming@users.noreply.github.com>
Date: Mon, 27 Nov 2023 16:38:51 -0800
Subject: [PATCH 2/2] Add `None` to Readme
---
README.md | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/README.md b/README.md
index 0f53b3d..c59ed8e 100644
--- a/README.md
+++ b/README.md
@@ -132,6 +132,23 @@ content := elem.Div(nil,
In this example, if `isAdmin` is `true`, the `Admin Panel` link is rendered. Otherwise, the `Login` link is rendered.
+#### `None` in Conditional Rendering
+
+`elem` provides a specialized node `None` that implements the `Node` interface but does not produce any visible output. It's particularly useful in scenarios where rendering nothing for a specific condition is required.
+
+```go
+showWelcomeMessage := false
+welcomeMessage := elem.Div(nil, elem.Text("Welcome to our website!"))
+// Using NoneNode for conditional rendering
+content := elem.Div(nil,
+ elem.If[elem.Node](showWelcomeMessage, welcomeMessage, elem.None()),
+)
+```
+
+In this example, `welcomeMessage` is rendered only if `showWelcomeMessage` is `true`. If it's `false`, `None` is rendered instead, which produces no visible output.
+
+Additionally, `None` can be used to create an empty element, as in `elem.Div(nil, elem.None())`, which results in ``. This can be handy for creating placeholders or structuring your HTML document without adding additional content.
+
### Supported Elements
`elem` provides utility functions for creating HTML elements: