Merge branch 'master' into fix/wrap-aliases

src/assets/JSAsset.js

@@ -149,7 +149,10 @@ class JSAsset extends Asset {
   }
 
   async pretransform() {
-    await this.loadSourceMap();
+    if (this.options.sourceMaps) {
+      await this.loadSourceMap();
+    }
+
     await babel(this);
 
     // Inline environment variables

src/assets/PugAsset.js

@@ -6,6 +6,7 @@ class PugAsset extends Asset {
   constructor(name, options) {
     super(name, options);
     this.type = 'html';
+    this.hmrPageReload = true;
   }
 
   async generate() {

src/packagers/JSConcatPackager.js

@@ -94,11 +94,13 @@ class JSConcatPackager extends Packager {
       let [source, name] = asset.cacheData.imports[identifier];
       let dep = asset.depAssets.get(asset.dependencies.get(source));
 
-      if (name === '*') {
-        this.markUsedExports(dep);
-      }
+      if (dep) {
+        if (name === '*') {
+          this.markUsedExports(dep);
+        }
 
-      this.markUsed(dep, name);
+        this.markUsed(dep, name);
+      }
     }
   }
 

src/transforms/terser.js

@@ -10,6 +10,7 @@ module.exports = async function(asset) {
   let customConfig = await asset.getConfig(['.uglifyrc', '.terserrc']);
   let options = {
     warnings: true,
+    safari10: true,
     mangle: {
       toplevel: !asset.options.scopeHoist
     }

test/integration/scope-hoisting/commonjs/wrap-optional/a.js

@@ -0,0 +1,6 @@
+try {
+    output = require('noop')
+}
+catch(_) {
+    output = 42
+}

test/scope-hoisting.js

@@ -1065,5 +1065,17 @@ describe('scope hoisting', function() {
       let output = await run(b);
       assert.deepEqual(output, 42);
     });
+
+    it('should support optional requires', async function() {
+      let b = await bundle(
+        path.join(
+          __dirname,
+          '/integration/scope-hoisting/commonjs/wrap-optional/a.js'
+        )
+      );
+
+      let output = await run(b);
+      assert.deepEqual(output, 42);
+    });
   });
 });