On-demand build time render for when using watch with the development server

package.json

@@ -104,7 +104,7 @@
     "sinon": "~4.5.0"
   },
   "dependencies": {
-    "@dojo/webpack-contrib": "7.0.0-alpha.6",
+    "@dojo/webpack-contrib": "7.0.0-alpha.8",
     "brotli-webpack-plugin": "1.0.0",
     "caniuse-lite": "1.0.30000973",
     "chalk": "2.4.1",

src/dev.config.ts

@@ -13,7 +13,7 @@ import ServiceWorkerPlugin, {
 import * as fs from 'fs';
 import * as path from 'path';
 import webpack = require('webpack');
-import BuildTimeRender from '@dojo/webpack-contrib/build-time-render/BuildTimeRender';
+import BuildTimeRender, { BuildTimeRenderArguments } from '@dojo/webpack-contrib/build-time-render/BuildTimeRender';
 import ExternalLoaderPlugin from '@dojo/webpack-contrib/external-loader-plugin/ExternalLoaderPlugin';
 import * as CleanWebpackPlugin from 'clean-webpack-plugin';
 import * as CopyWebpackPlugin from 'copy-webpack-plugin';
@@ -119,15 +119,29 @@ window['${libraryName}'].base = '${base}'</script>`,
 		});
 	}
 
+	const btrOptions: BuildTimeRenderArguments = args['build-time-render'];
 	if (args['build-time-render']) {
+		const paths = btrOptions.paths || [];
+		let isStatic = btrOptions.static;
+		if (isStatic === true) {
+			for (let i = 0; i < paths.length; i++) {
+				const path = paths[i];
+				if (typeof path === 'object' && path.static === false) {
+					isStatic = false;
+					break;
+				}
+			}
+		}
+
 		config.plugins.push(
 			new BuildTimeRender({
-				...args['build-time-render'],
+				...btrOptions,
 				sync: singleBundle,
 				entries: Object.keys(config.entry!),
 				basePath,
 				baseUrl: base,
-				scope: libraryName
+				scope: libraryName,
+				watch: Boolean(args.watch && args.serve && isStatic)
 			})
 		);
 	}

src/dist.config.ts

@@ -1,4 +1,4 @@
-import BuildTimeRender from '@dojo/webpack-contrib/build-time-render/BuildTimeRender';
+import BuildTimeRender, { BuildTimeRenderArguments } from '@dojo/webpack-contrib/build-time-render/BuildTimeRender';
 import ExternalLoaderPlugin from '@dojo/webpack-contrib/external-loader-plugin/ExternalLoaderPlugin';
 import BundleAnalyzerPlugin from '@dojo/webpack-contrib/webpack-bundle-analyzer/BundleAnalyzerPlugin';
 import ServiceWorkerPlugin, {
@@ -122,15 +122,28 @@ function webpackConfig(args: any): webpack.Configuration {
 		new CleanWebpackPlugin(['dist', 'info'], { root: output!.path, verbose: false })
 	].filter((item) => item);
 
+	const btrOptions: BuildTimeRenderArguments = args['build-time-render'];
 	if (args['build-time-render']) {
+		const paths = btrOptions.paths || [];
+		let isStatic = btrOptions.static;
+		if (isStatic === true) {
+			for (let i = 0; i < paths.length; i++) {
+				const path = paths[i];
+				if (typeof path === 'object' && path.static === false) {
+					isStatic = false;
+					break;
+				}
+			}
+		}
 		config.plugins.push(
 			new BuildTimeRender({
-				...args['build-time-render'],
+				...btrOptions,
 				entries: Object.keys(config.entry!),
 				sync: args.singleBundle,
 				basePath,
 				baseUrl: base,
-				scope: libraryName
+				scope: libraryName,
+				watch: Boolean(args.watch && args.serve && btrOptions.static)
 			})
 		);
 	}

src/main.ts

@@ -11,9 +11,11 @@ import * as https from 'https';
 import * as expressCompression from 'compression';
 import * as proxy from 'http-proxy-middleware';
 import * as history from 'connect-history-api-fallback';
+import BuildTimeRender, { BuildTimeRenderArguments } from '@dojo/webpack-contrib/build-time-render/BuildTimeRender';
 
 const pkgDir = require('pkg-dir');
 const expressStaticGzip = require('express-static-gzip');
+import { libraryName } from './base.config';
 import devConfigFactory from './dev.config';
 import unitConfigFactory from './unit.config';
 import functionalConfigFactory from './functional.config';
@@ -28,6 +30,8 @@ const connectInject = require('connect-inject');
 
 const testModes = ['test', 'unit', 'functional'];
 
+const btrPages = new Set<string>();
+
 function createCompiler(config: webpack.Configuration) {
 	const compiler = webpack(config);
 	fixMultipleWatchTrigger(compiler);
@@ -150,6 +154,45 @@ function serve(config: webpack.Configuration, args: any): Promise<void> {
 	});
 
 	const outputDir = (config.output && config.output.path) || process.cwd();
+	const jsonpName = (config.output && config.output.jsonpFunction) || 'unknown';
+	const btrOptions: BuildTimeRenderArguments = args['build-time-render'];
+
+	let isStaticBtr = btrOptions.static;
+	if (btrOptions) {
+		const paths = btrOptions.paths || [];
+		isStaticBtr = btrOptions.static;
+		if (isStaticBtr === true) {
+			for (let i = 0; i < paths.length; i++) {
+				const path = paths[i];
+				if (typeof path === 'object' && path.static === false) {
+					isStaticBtr = false;
+					break;
+				}
+			}
+		}
+
+	if (args.watch && isStaticBtr) {
+		app.use(base, (req, _, next) => {
+			const { pathname: originalPath } = url.parse(req.url);
+			if (req.accepts('html') && originalPath && !originalPath.match(/\..*$/) && !btrPages.has(originalPath)) {
+				const path = originalPath.replace(/^\//, '').replace(/\/$/, '');
+				const btr = new BuildTimeRender({
+					...args['build-time-render'],
+					scope: libraryName,
+					baseUrl: args.base || '/',
+					discoverPaths: false,
+					basePath: process.cwd(),
+					entries: Object.keys(config.entry!)
+				});
+
+				btrPages.add(originalPath);
+				btr.runSinglePath(next, path, outputDir, jsonpName);
+			} else {
+				next();
+			}
+		});
+	}
+
 	if (args.mode !== 'dist' || !Array.isArray(args.compression)) {
 		app.use(base, expressCompression());
 	}