fix: disable load manifest in dev (#1711)

* fix: Ensure load-manifest is only generated in prod

* docs: Adding changeset

* fix: devServer live reload with `--esm` flag

Author: rschristian

.changeset/tiny-books-flash.md

@@ -0,0 +1,5 @@
+---
+'preact-cli': patch
+---
+
+Fix ensures that the load-manifest is only attempted to be built in prod. It serves no use in dev (as preloading is limited to prod) and can create a race condition when used alongside HMR.

packages/cli/lib/lib/webpack/create-load-manifest.js

@@ -1,4 +1,5 @@
-module.exports = (assets, namedChunkGroups) => {
+module.exports = (assets, namedChunkGroups, isProd) => {
+	if (!isProd) return {};
 	/**
 	 * This is a mapping of generic/pre-build filenames to their postbuild output
 	 *

packages/cli/lib/lib/webpack/push-manifest.js

@@ -2,6 +2,9 @@ const webpack = require('webpack');
 const createLoadManifest = require('./create-load-manifest');
 
 module.exports = class PushManifestPlugin {
+	constructor(isProd) {
+		this.isProd = isProd;
+	}
 	apply(compiler) {
 		compiler.hooks.emit.tap(
 			{
@@ -11,7 +14,8 @@ module.exports = class PushManifestPlugin {
 			compilation => {
 				const manifest = createLoadManifest(
 					compilation.assets,
-					compilation.namedChunkGroups
+					compilation.namedChunkGroups,
+					this.isProd
 				);
 
 				let output = JSON.stringify(manifest);

packages/cli/lib/lib/webpack/render-html-plugin.js

@@ -89,7 +89,7 @@ module.exports = async function (config) {
 				if (assets['push-manifest.json']) {
 					return JSON.parse(assets['push-manifest.json'].source());
 				}
-				return createLoadManifest(assets, namedChunkGroups);
+				return createLoadManifest(assets, namedChunkGroups, config.isProd);
 			},
 			config,
 			url,

packages/cli/lib/lib/webpack/webpack-client-config.js

@@ -146,7 +146,7 @@ async function clientConfig(env) {
 				'process.env.ADD_SW': env.sw,
 				'process.env.PRERENDER': env.prerender,
 			}),
-			new PushManifestPlugin(),
+			new PushManifestPlugin(env.isProd),
 			...(await renderHTMLPlugin(env)),
 			...getBabelEsmPlugin(env),
 			copyPatterns.length !== 0 &&
@@ -331,7 +331,7 @@ function isDev(env) {
 		].filter(Boolean),
 
 		devServer: {
-			hot: true,
+			hot: env.refresh,
 			liveReload: !env.refresh,
 			compress: true,
 			devMiddleware: {