Merge pull request #9 from chasefleming/chasefleming/render-perf-impr…

…ovements

Performance Improvements

elem.go

@@ -2,8 +2,31 @@ package elem
 
 import (
 	"sort"
+	"strings"
 )
 
+// List of HTML5 void elements. Void elements, also known as self-closing or empty elements,
+// are elements that don't have a closing tag because they can't contain any content.
+// For example, the <img> tag cannot wrap text or other tags, it stands alone, so it doesn't have a closing tag.
+var voidElements = map[string]struct{}{
+	"area":    {},
+	"base":    {},
+	"br":      {},
+	"col":     {},
+	"command": {},
+	"embed":   {},
+	"hr":      {},
+	"img":     {},
+	"input":   {},
+	"keygen":  {},
+	"link":    {},
+	"meta":    {},
+	"param":   {},
+	"source":  {},
+	"track":   {},
+	"wbr":     {},
+}
+
 type Attrs map[string]string
 
 type Element struct {
@@ -12,36 +35,10 @@ type Element struct {
 	Children []interface{} // Can be either string (for text) or another Element
 }
 
-func NewElement(tag string, attrs Attrs, children ...interface{}) *Element {
-	return &Element{
-		Tag:      tag,
-		Attrs:    attrs,
-		Children: children,
-	}
-}
-
-func (e *Element) Render() string {
-	// List of HTML5 void elements. Void elements, also known as self-closing or empty elements,
-	// are elements that don't have a closing tag because they can't contain any content.
-	// For example, the <img> tag cannot wrap text or other tags, it stands alone, so it doesn't have a closing tag.
-	var voidElements = map[string]bool{
-		"area":    true,
-		"base":    true,
-		"br":      true,
-		"col":     true,
-		"command": true,
-		"embed":   true,
-		"hr":      true,
-		"img":     true,
-		"input":   true,
-		"keygen":  true,
-		"link":    true,
-		"meta":    true,
-		"param":   true,
-		"source":  true,
-		"track":   true,
-		"wbr":     true,
-	}
+func (e *Element) RenderTo(builder *strings.Builder) {
+	// Start with opening tag
+	builder.WriteString("<")
+	builder.WriteString(e.Tag)
 
 	// Sort the keys for consistent order
 	keys := make([]string, 0, len(e.Attrs))
@@ -50,25 +47,50 @@ func (e *Element) Render() string {
 	}
 	sort.Strings(keys)
 
-	props := ""
+	// Append the attributes to the builder
 	for _, k := range keys {
-		props += ` ` + k + `="` + e.Attrs[k] + `"`
+		builder.WriteString(` `)
+		builder.WriteString(k)
+		builder.WriteString(`="`)
+		builder.WriteString(e.Attrs[k])
+		builder.WriteString(`"`)
+	}
+
+	// If it's a void element, close it and return
+	if _, exists := voidElements[e.Tag]; exists {
+		builder.WriteString(`>`)
+		return
 	}
 
-	content := ""
+	// Close opening tag
+	builder.WriteString(`>`)
+
+	// Build the content (either child text or nested elements)
 	for _, child := range e.Children {
 		switch c := child.(type) {
 		case string:
-			content += c
+			builder.WriteString(c)
 		case *Element:
-			content += c.Render()
+			c.RenderTo(builder)
 		}
 	}
 
-	// Check if the tag is a void element and doesn't have any content
-	if content == "" && voidElements[e.Tag] {
-		return `<` + e.Tag + props + `>` // No closing tag for void elements
-	}
+	// Append closing tag
+	builder.WriteString(`</`)
+	builder.WriteString(e.Tag)
+	builder.WriteString(`>`)
+}
+
+func (e *Element) Render() string {
+	var builder strings.Builder
+	e.RenderTo(&builder)
+	return builder.String()
+}
 
-	return `<` + e.Tag + props + `>` + content + `</` + e.Tag + `>`
+func NewElement(tag string, attrs Attrs, children ...interface{}) *Element {
+	return &Element{
+		Tag:      tag,
+		Attrs:    attrs,
+		Children: children,
+	}
 }