From 27e6e266041e8969357d5100ead3f2a653fadf87 Mon Sep 17 00:00:00 2001
From: sunfmin <sunfmin@gmail.com>
Date: Fri, 3 Jan 2020 15:45:14 +0800
Subject: [PATCH] Add Iff to pass body as an func in

---
 README.md       | 24 ++++++++++++++++++++++++
 example_test.go | 26 ++++++++++++++++++++++++++
 if.go           | 41 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 91 insertions(+)

diff --git a/README.md b/README.md
index 3211a38..2631b82 100644
--- a/README.md
+++ b/README.md
@@ -314,5 +314,29 @@ An example show how to set styles
 	// <div style='background-color:red; border:1px solid red; color:blue;'></div>
 ```
 
+An example to use If, `Iff` is for body to passed in as an func for the body depends on if condition not to be nil, `If` is for directly passed in HTMLComponent
+```go
+	type Person struct {
+	    Age int
+	}
+	var p *Person
+	
+	name := "Leon"
+	comp := Div(
+	    Iff(p != nil && p.Age > 18, func() HTMLComponent {
+	        return Div().Text(name + ": Age > 18")
+	    }).ElseIf(p == nil, func() HTMLComponent {
+	        return Div().Text("No person named " + name)
+	    }).Else(func() HTMLComponent {
+	        return Div().Text(name + ":Age <= 18")
+	    }),
+	)
+	Fprint(os.Stdout, comp, context.TODO())
+	//Output:
+	// <div>
+	// <div>No person named Leon</div>
+	// </div>
+```
+
 
 
diff --git a/example_test.go b/example_test.go
index 7866184..1f1aad4 100644
--- a/example_test.go
+++ b/example_test.go
@@ -358,3 +358,29 @@ func ExampleTag_08styles() {
 	//Output:
 	// <div style='background-color:red; border:1px solid red; color:blue;'></div>
 }
+
+/*
+An example to use If, `Iff` is for body to passed in as an func for the body depends on if condition not to be nil, `If` is for directly passed in HTMLComponent
+*/
+func ExampleTag_09iff() {
+	type Person struct {
+		Age int
+	}
+	var p *Person
+
+	name := "Leon"
+	comp := Div(
+		Iff(p != nil && p.Age > 18, func() HTMLComponent {
+			return Div().Text(name + ": Age > 18")
+		}).ElseIf(p == nil, func() HTMLComponent {
+			return Div().Text("No person named " + name)
+		}).Else(func() HTMLComponent {
+			return Div().Text(name + ":Age <= 18")
+		}),
+	)
+	Fprint(os.Stdout, comp, context.TODO())
+	//Output:
+	// <div>
+	// <div>No person named Leon</div>
+	// </div>
+}
diff --git a/if.go b/if.go
index 87db45d..c32746c 100644
--- a/if.go
+++ b/if.go
@@ -42,3 +42,44 @@ func (b *IfBuilder) MarshalHTML(ctx context.Context) (r []byte, err error) {
 	}
 	return HTMLComponents(b.comps).MarshalHTML(ctx)
 }
+
+type IfFuncBuilder struct {
+	f   func() HTMLComponent
+	set bool
+}
+
+func Iff(v bool, f func() HTMLComponent) (r *IfFuncBuilder) {
+	r = &IfFuncBuilder{}
+	if v {
+		r.f = f
+		r.set = true
+	}
+	return
+}
+
+func (b *IfFuncBuilder) ElseIf(v bool, f func() HTMLComponent) (r *IfFuncBuilder) {
+	if b.set {
+		return b
+	}
+	if v {
+		b.f = f
+		b.set = true
+	}
+	return b
+}
+
+func (b *IfFuncBuilder) Else(f func() HTMLComponent) (r *IfFuncBuilder) {
+	if b.set {
+		return b
+	}
+	b.set = true
+	b.f = f
+	return b
+}
+
+func (b *IfFuncBuilder) MarshalHTML(ctx context.Context) (r []byte, err error) {
+	if b.f == nil {
+		return
+	}
+	return b.f().MarshalHTML(ctx)
+}