[web-client] simple theme: build & development env based on vite.

Vite is a build tool, it consists of two major parts [1]:

- A dev server that provides rich feature enhancements over native ES modules,
  for example extremely fast Hot Module Replacement (HMR).

- A build command that bundles your code with Rollup, pre-configured to output
  highly optimized static assets for production.

[1] https://vite.dev/guide/

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

client/simple/vite.config.js

@@ -0,0 +1,121 @@
+/**
+ * CONFIG: https://vite.dev/config/
+ */
+
+import { resolve } from "node:path";
+import { defineConfig } from "vite";
+import { viteStaticCopy } from "vite-plugin-static-copy";
+
+
+const ROOT = "../..";  // root of the git reposetory
+
+const PATH = {
+
+  dist: resolve(ROOT, "searx/static/themes/simple"),
+  // dist: resolve(ROOT, "client/simple/dist"),
+
+  src: "src",
+  modules: "node_modules",
+  brand: "src/brand",
+  static: resolve(ROOT, "client/simple/static"),
+  leaflet: resolve(ROOT, "client/simple/node_modules/leaflet/dist"),
+  templates: resolve(ROOT, "searx/templates/simple"),
+};
+
+
+};
+
+
+export default defineConfig({
+
+  root: PATH.src,
+  mode: "production",
+  // mode: "development",
+
+  // FIXME: missing CCS sourcemaps!!
+  // see: https://github.com/vitejs/vite/discussions/13845#discussioncomment-11992084
+  //
+  // what I have tried so far (see config below):
+  //
+  // - build.sourcemap
+  // - esbuild.sourcemap
+  // - css.preprocessorOptions.less.sourceMap
+
+  css: {
+    devSourcemap: true,
+    preprocessorOptions: {
+      less: {
+        // FIXME: missing CCS sourcemaps!!
+        sourceMap: {
+          outputSourceFiles: true,
+          sourceMapURL: (name) => { const s = name.split('/'); return s[s.length - 1] + '.map'; },
+        },
+        // env: 'development',
+        // relativeUrls: true,
+        // javascriptEnabled: true,
+      },
+    },
+  },  // end: css
+
+  esbuild : {
+    // FIXME: missing CCS sourcemaps!!
+    sourcemap: true
+  },
+
+  build: {
+    manifest: "manifest.json",
+    emptyOutDir: true,
+    assetsDir: "",
+    outDir: PATH.dist,
+
+    // FIXME: missing CCS sourcemaps!!
+    sourcemap: true,
+
+    // https://vite.dev/config/build-options.html#build-cssminify
+    cssMinify: true,
+    // cssMinify: "esbuild",
+    minify: "esbuild",
+
+    rollupOptions: {
+      input: {
+
+        // build CSS files
+        "css/searxng.min.css": PATH.src + "/less/style-ltr.less",
+        "css/searxng-rtl.min.css": PATH.src + "/less/style-rtl.less",
+        "css/rss.min.css": PATH.src + "/less/rss.less",
+
+        // build JS files
+        "js/searxng.head.min": PATH.src + "/js/searxng.head.js",
+        "js/searxng.min": PATH.src + "/js/searxng.js",
+
+      },
+
+      // file naming conventions / pathnames are relative to outDir (PATH.dist)
+      output: {
+        entryFileNames: "[name].js",
+        chunkFileNames: "[name].js",
+        assetFileNames: "[name].[ext]",
+        // Vite does not support "rollupOptions.output.sourcemap".
+        // Please use "build.sourcemap" instead.
+        // sourcemap: true,
+      },
+
+    },
+  },  // end: build
+
+  plugins: [
+
+    // Leaflet
+
+    viteStaticCopy({
+      targets: [
+        { src: PATH.leaflet + "/leaflet.{js,js.map}", dest: PATH.dist + "/js" },
+        { src: PATH.leaflet + "/images/*.png", dest: PATH.dist + "/css/images/" },
+        { src: PATH.leaflet + "/*.{css,css.map}", dest: PATH.dist + "/css" },
+        { src: PATH.static + "/**/*", dest: PATH.dist },
+      ]
+    })
+  ],
+  ] // end: plugins
+
+});