Add file filter loader

Author: Malachirwin

lib/generators/lightning_cad/templates/app/javascript/helpers/hooks.js

@@ -1,5 +1,6 @@
 import path from 'node:path'
 import * as glob from 'glob'
+import filterFile from '../../../config/webpack/loaders/filter-file.js'
 
 const shorthandRoot = path.join(process.cwd(), 'app/javascript')
 const config = {
@@ -19,8 +20,18 @@ export function resolve(specifier, context, nextResolve) {
   return nextResolve(finalSpecifier, context)
 }
 
-export function load(specifier, context, nextLoad) {
-  if (!specifier.includes('*')) return nextLoad(specifier, context)
+export async function load(specifier, context, nextLoad) {
+  if (!specifier.includes('*')) {
+    const result = await nextLoad(specifier, context)
+    if (!result.source) return result
+
+    const source = filterFile(result.source, 'server')
+
+    return {
+      ...result,
+      source
+    }
+  }
 
   const pattern = specifier.replace('file://', '')
   const paths = glob.globSync(pattern, { nodir: true })

lib/generators/lightning_cad/templates/config/webpack/loaders/filter-file.js

@@ -0,0 +1,26 @@
+/**
+ * Webpack loader to filter server-only or client-only sections of code out of
+ * a file, based on the current target (e.g., 'web' or 'node')
+ */
+export default function (source, target = this.target) {
+  let begin, end
+  if (target === 'web') {
+    begin = '// @begin-server-only'
+    end = '// @end-server-only'
+  } else {
+    begin = '// @begin-client-only'
+    end = '// @end-client-only'
+  }
+
+  let filteredSource = source
+  let beginIndex = filteredSource.indexOf(begin)
+  let endIndex = filteredSource.indexOf(end)
+  while (beginIndex !== -1) {
+    const afterExcludedBlock = endIndex === -1 ? '' : filteredSource.slice(endIndex + end.length)
+    filteredSource = filteredSource.slice(0, beginIndex) + afterExcludedBlock
+    beginIndex = filteredSource.indexOf(begin)
+    endIndex = filteredSource.indexOf(end)
+  }
+
+  return filteredSource
+}

lib/generators/lightning_cad/webpack_generator.rb

@@ -55,7 +55,14 @@ def add_resolve_aliases
     def add_loaders
       say 'Adding loaders to the config'
 
+      copy_file 'config/webpack/loaders/filter-file.js'
+
       loaders = <<-JS
+,
+      {
+        test: /\.jsx?$/,
+        use: path.resolve('./config/webpack/loaders/filter-file.js')
+      },
       {
         test: /\.(mjs|cjs|js|jsx)$/,
         loader: 'import-glob'
@@ -66,7 +73,7 @@ def add_loaders
       },
       JS
 
-      insert_into_file 'webpack.config.js', loaders, after: "rules: [\n"
+      insert_into_file 'webpack.config.js', loaders, after: "'postcss-loader'\n        ]\n      }"
     end
 
     def add_terser_plugin_options