Set slice capacity based on input in `Map` and `Classes.Render` (#243)

Hey! I just discovered this repo and I love being able to write
templates while still having compile-time checks.

I was looking through the code and noticed slices aren't currently
preallocated in `Map()` and `Classes.Render()`. Preallocating will
improve performance since the resulting slice won't have to be grown
dynamically during the append loop.

2 files changed, 2 insertions, 2 deletions

diff --git a/components/components.go b/components/components.go
index 122882f..d37ccf4 100644
--- a/components/components.go
+++ b/components/components.go
@@ -44,7 +44,7 @@ type Classes map[string]bool
 
 // Render satisfies [g.Node].
 func (c Classes) Render(w io.Writer) error {
-	var included []string
+	included := make([]string, 0, len(c))
 	for c, include := range c {
 		if include {
 			included = append(included, c)
diff --git a/gomponents.go b/gomponents.go
index 735ad00..ad9c2cd 100644
--- a/gomponents.go
+++ b/gomponents.go
@@ -250,7 +250,7 @@ func Rawf(format string, a ...interface{}) Node {
 
 // Map a slice of anything to a [Group] (which is just a slice of [Node]-s).
 func Map[T any](ts []T, cb func(T) Node) Group {
-	var nodes []Node
+	nodes := make([]Node, 0, len(ts))
 	for _, t := range ts {
 		nodes = append(nodes, cb(t))
 	}