Allow for transformation of source and compiled code, handle use dire…

…ctive

README.md

@@ -18,21 +18,14 @@ See [./test](./test).
     rules: [
       {
         test: /\.htl$/,
-        use: {
-          loader: "htl-loader",
-          options: {
-            globalName: "htl"
-          }
-        }
+        use: ["htl-loader"]
       }
     ]
-  },
-  node: {
-    fs: "empty"
   }
 }
 ```
 
+
 2. Create examplary `template.htl`:
 
 ```html
@@ -53,6 +46,52 @@ import template from "./template.htl";
 })();
 ```
 
+## Advanced
+
+```js
+{
+  module: {
+    rules: [
+      {
+        test: /\.htl$/,
+        use: [
+          {
+            loader: "htl-loader",
+            options: {
+              // Remove directives `@adobe/htlengine` does not understand
+              transformSource: source => {
+                const output = source
+                  .replace(/data-sly-use\.templates?="(.*?)"/g, "")
+                  .replace(/<sly[^>]+data-sly-call=(["']).*?\1.*?><\/sly>/g, "");
+
+                return output;
+              },
+              // Allow for custom models in data from `use` directives
+              transformCompiled: (compiled, settings) => {
+                const output = compiled.replace(
+                  /(new Runtime\(\);)/,
+                  `$1
+                  const originalUse = runtime.use.bind(runtime);
+                  runtime.use = function(uri, options) {
+                    const settings = Object.assign({
+                      model: '${settings.model}'
+                    }, options);
+                    return originalUse(uri, settings);
+                  }`
+                );
+
+                return output;
+              },
+              useDir: path.resolve(__dirname, "../src/htlmocks")
+            }
+          }
+        ]
+      }
+    ]
+  }
+}
+```
+
 ## License
 
 [MIT](http://www.opensource.org/licenses/mit-license)

index.js

@@ -1,24 +1,60 @@
-const { getOptions } = require("loader-utils");
+const fs = require("fs");
+const path = require("path");
+const { getOptions, parseQuery } = require("loader-utils");
 const { Compiler } = require("@adobe/htlengine");
 
 module.exports = async function(source) {
   const options = getOptions(this);
+  const query = this.resourceQuery ? parseQuery(this.resourceQuery) : null;
   const settings = Object.assign(
     {
-      globalName: "htl"
+      globalName: "htl",
+      model: "default",
+      useDir: null,
+      transformSource: null,
+      transformCompiled: null
     },
-    options
+    options,
+    query
   );
 
+  let input = source;
+
+  // Optionally transform source, e.g. remove directives `@adobe/htlengine` does not understand
+  if (settings.transformSource) {
+    input = settings.transformSource(source, settings);
+  }
+
+  // Set up compiler
   const compiler = new Compiler()
     .includeRuntime(true)
     .withRuntimeGlobalName(settings.globalName);
 
-  const compiledCode = await compiler.compileToString(source);
+  // Compile
+  let compiledCode = await compiler.compileToString(input);
+
+  // Specify location for data files from `use` directives
+  if (settings.useDir) {
+    // Remove files from cache
+    fs.readdirSync(settings.useDir).forEach(file => {
+      const filePath = path.join(settings.useDir, file);
+      delete require.cache[filePath];
+    });
+
+    compiledCode = compiledCode.replace(
+      /(runtime\.setGlobal\(resource\);)/,
+      `$1\nruntime.withUseDirectory('${settings.useDir}');`
+    );
+  }
+
+  // Optionally transform compiled, e.g. to customize runtime
+  if (settings.transformCompiled) {
+    compiledCode = settings.transformCompiled(compiledCode, settings);
+  }
+
+  // Run
+  const template = eval(compiledCode);
+  const html = await template({});
 
-  return `
-    ${compiledCode}
-    const template = module.exports.main;
-    module.exports = async (data) => await template(data);
-  `;
+  return `module.exports = \`${html}\``;
 };