From 0ba806866a805859bdf0e2802a8af70cbe868e78 Mon Sep 17 00:00:00 2001
From: Marvin Hagemeister <hello@marvinh.dev>
Date: Sat, 13 Mar 2021 18:36:27 +0100
Subject: [PATCH] Improve main entry detection logic

Instead of manually parsing the HTML we rely on the resolveId hook
which tells us who imported the current file. Didn't know about that
before. This is much nicer!
---
 src/devtools.ts | 32 ++++++++++++++++++++------------
 1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/src/devtools.ts b/src/devtools.ts
index 8f9c2c8..5c42e68 100644
--- a/src/devtools.ts
+++ b/src/devtools.ts
@@ -13,30 +13,38 @@ export function preactDevtoolsPlugin({
 
 	let entry = "";
 	let config: ResolvedConfig;
+	let found = false;
 
 	const plugin: Plugin = {
 		name: "preact:devtools",
 
+		// Ensure that we resolve before everything else
+		enforce: "pre",
+
 		configResolved(resolvedConfig) {
 			config = resolvedConfig;
 		},
 
-		transformIndexHtml(html) {
-			// Use this to grab the initial entry js file to
-			// inject "preact/debug" into at a later stage.
-			const match = html.match(/<script type=["]module["] src=["](.*?)["]/);
-
-			if (!match || !match.length) {
-				throw new Error(`Didn't find entry script tag in index.html`);
+		resolveId(id, importer = "") {
+			// Get the main entry file to inject into
+			if (
+				!found &&
+				/\.html$/.test(importer) &&
+				!/\/node_modules\//.test(id) &&
+				/\.[tj]sx?$/.test(id)
+			) {
+				found = true;
+				entry = path.join(config.root, id);
+
+				// TODO: Vite types require explicit return
+				// undefined here. They're lacking the "void" type
+				// in their declarations
+				return undefined;
 			}
-
-			entry = path.join(config.root, match[1]);
-			return html;
 		},
 
 		transform(code, id) {
-			// Inject "preact/debug" or "preact/devtools" respectively
-			if ((entry === id && config.command === "serve") || injectInProd) {
+			if (entry === id && (config.command === "serve" || injectInProd)) {
 				const source = injectInProd ? "preact/devtools" : "preact/debug";
 				code = `import "${source}";\n${code}`;