perf: cache resolved urls

plugins/css_bundler/src/builder.ts

@@ -1,6 +1,6 @@
 import { join, parse, resolve, toFileUrl } from '$std/path/mod.ts'
 import { bundleAsync } from 'lightningcss'
-import { Logger, cssImports, uInt8ArrayConcat } from './helpers.ts'
+import { cssImports, cssUrls, Logger, uInt8ArrayConcat } from './helpers.ts'
 
 export async function builder(
 	{ filename, dev, assetDir, remote }: {
@@ -91,17 +91,23 @@ export async function builder(
 					cache(url, remote, assetDir)
 				}
 				return { loc, url }
-			}
-		}
+			},
+		},
 	})
 
 	return { code, map }
 }
 
 async function cache(url: string, base: string, assetDir: string) {
+	const filepath = join(assetDir, url.split('?')[0])
 	const fullUrl = new URL(url, base)
+
+	if (cssUrls.has(fullUrl.pathname)) {
+		return
+	}
+
+	cssUrls.set(fullUrl.pathname, filepath)
 	const response = await fetch(fullUrl)
 	const file = await response.arrayBuffer()
-	const filepath = join(assetDir, url.split('?')[0])
 	await Deno.writeFile(filepath, new Uint8Array(file))
 }

plugins/css_bundler/src/helpers.ts

@@ -26,6 +26,7 @@ export async function hashFile(file: ArrayBuffer): Promise<string> {
 }
 
 export const cssImports: Map<string, string> = new Map()
+export const cssUrls: Map<string, string> = new Map()
 
 export function uInt8ArrayConcat(a: Uint8Array, b: Uint8Array) {
 	const dest = new Uint8Array(a.length + b.length)

plugins/css_bundler/src/middleware.ts

@@ -43,8 +43,8 @@ export function cssHandler(sourceDir: string): MiddlewareHandler {
 
 				return new Response(file, {
 					headers: {
-						'Content-Type': contentType(ext) ?? 'text/plain; charset=utf-8'
-					}
+						'Content-Type': contentType(ext) ?? 'text/plain; charset=utf-8',
+					},
 				})
 			} catch {
 				return resp