WIP: Per-source minification (DO NOT MERGE)

scripts/build.js

@@ -36,6 +36,10 @@ async function main() {
     __dirname + "/../src/loaders/shebang-loader"
   );
 
+  const { code: terserLoader, assets: terserLoaderAssets } = await ncc(
+    __dirname + "/../src/loaders/terser-loader"
+  );
+
   const { code: tsLoader, assets: tsLoaderAssets } = await ncc(
     __dirname + "/../src/loaders/ts-loader"
   );
@@ -51,6 +55,7 @@ async function main() {
     Object.keys(nodeLoaderAssets).length ||
     Object.keys(relocateLoaderAssets).length ||
     Object.keys(shebangLoaderAssets).length ||
+    Object.keys(terserLoaderAssets).length ||    
     Object.keys(tsLoaderAssets).some(asset => !asset.startsWith('lib/')) ||
     Object.keys(sourcemapAssets).length
   ) {
@@ -63,6 +68,7 @@ async function main() {
   writeFileSync(__dirname + "/../dist/ncc/loaders/node-loader.js", nodeLoader);
   writeFileSync(__dirname + "/../dist/ncc/loaders/relocate-loader.js", relocateLoader);
   writeFileSync(__dirname + "/../dist/ncc/loaders/shebang-loader.js", shebangLoader);
+  writeFileSync(__dirname + "/../dist/ncc/loaders/terser-loader.js", terserLoader);  
   writeFileSync(__dirname + "/../dist/ncc/loaders/ts-loader.js", tsLoader);
 
   // copy typescript types

src/index.js

@@ -136,7 +136,14 @@ module.exports = async (
               }
             }
           }]
-        }
+        },
+        ...minify ? [{
+          test: /\.(js|mjs|tsx?)$/,
+          use: [{
+            loader: __dirname + "/loaders/terser-loader.js",
+            options: { sourceMap }
+          }]
+        }] : []
       ]
     },
     plugins: [
@@ -263,7 +270,7 @@ module.exports = async (
     if (map)
       map.mappings = ";" + map.mappings;
     return { code, map, assets };
-  })
+  });
 };
 
 // this could be rewritten with actual FS apis / globs, but this is simpler

src/loaders/terser-loader.js

@@ -0,0 +1,21 @@
+const terser = require("terser");
+const { getOptions } = require('loader-utils');
+
+module.exports = function (code) {
+  const options = getOptions(this);
+  const result = terser.minify(code, {
+    compress: {
+      keep_classnames: true,
+      keep_fnames: true
+    },
+    mangle: {
+      keep_classnames: true,
+      keep_fnames: true
+    },
+    sourceMap: options.sourceMap
+  });
+  // For some reason, auth0 returns "undefined"!
+  if (result.code === undefined)
+    return this.callback(null, code);
+  return this.callback(null, result.code, result.map);
+};