refactor(html): share deterministic attribute rendering

Co-Authored-By: Virgil <virgil@lethean.io>

layout.go

@@ -3,7 +3,6 @@ package html
 import (
 	"errors"
 	"maps"
-	"slices"
 	"strconv"
 	"strings"
 )
@@ -224,20 +223,9 @@ func (l *Layout) Render(ctx *Context) string {
 
 		b.WriteByte('<')
 		b.WriteString(escapeHTML(meta.tag))
-		if len(l.attrs) > 0 {
-			keys := slices.Collect(maps.Keys(l.attrs))
-			slices.Sort(keys)
-			for _, key := range keys {
-				if key == "role" || key == "data-block" {
-					continue
-				}
-				b.WriteByte(' ')
-				b.WriteString(escapeHTML(key))
-				b.WriteString(`="`)
-				b.WriteString(escapeAttr(l.attrs[key]))
-				b.WriteByte('"')
-			}
-		}
+		writeSortedAttrs(&b, l.attrs, func(key string) bool {
+			return key == "role" || key == "data-block"
+		})
 		b.WriteString(` role="`)
 		b.WriteString(escapeAttr(meta.role))
 		b.WriteString(`" data-block="`)

node.go

@@ -117,6 +117,28 @@ func escapeAttr(s string) string {
 	return html.EscapeString(s)
 }
 
+// writeSortedAttrs renders a deterministic attribute list to the builder.
+// An optional skip callback can omit reserved keys while preserving ordering
+// for the remaining attributes.
+func writeSortedAttrs(b *strings.Builder, attrs map[string]string, skip func(string) bool) {
+	if len(attrs) == 0 {
+		return
+	}
+
+	keys := slices.Collect(maps.Keys(attrs))
+	slices.Sort(keys)
+	for _, key := range keys {
+		if skip != nil && skip(key) {
+			continue
+		}
+		b.WriteByte(' ')
+		b.WriteString(escapeHTML(key))
+		b.WriteString(`="`)
+		b.WriteString(escapeAttr(attrs[key]))
+		b.WriteByte('"')
+	}
+}
+
 // --- rawNode ---
 
 type rawNode struct {
@@ -622,16 +644,7 @@ func (n *elNode) renderWithPath(ctx *Context, path string) string {
 	b.WriteByte('<')
 	b.WriteString(escapeHTML(n.tag))
 
-	// Sort attribute keys for deterministic output.
-	keys := slices.Collect(maps.Keys(n.attrs))
-	slices.Sort(keys)
-	for _, key := range keys {
-		b.WriteByte(' ')
-		b.WriteString(escapeHTML(key))
-		b.WriteString(`="`)
-		b.WriteString(escapeAttr(n.attrs[key]))
-		b.WriteByte('"')
-	}
+	writeSortedAttrs(&b, n.attrs, nil)
 
 	b.WriteByte('>')
 

responsive.go

@@ -2,7 +2,6 @@ package html
 
 import (
 	"maps"
-	"slices"
 	"strconv"
 	"strings"
 )
@@ -232,20 +231,9 @@ func (r *Responsive) renderWithPath(ctx *Context, path string) string {
 	var b strings.Builder
 	for _, v := range r.variants {
 		b.WriteString(`<div`)
-		if len(r.attrs) > 0 {
-			keys := slices.Collect(maps.Keys(r.attrs))
-			slices.Sort(keys)
-			for _, key := range keys {
-				if key == "data-variant" {
-					continue
-				}
-				b.WriteByte(' ')
-				b.WriteString(escapeHTML(key))
-				b.WriteString(`="`)
-				b.WriteString(escapeAttr(r.attrs[key]))
-				b.WriteByte('"')
-			}
-		}
+		writeSortedAttrs(&b, r.attrs, func(key string) bool {
+			return key == "data-variant"
+		})
 		b.WriteString(` data-variant="`)
 		b.WriteString(escapeAttr(v.name))
 		b.WriteString(`">`)