Deploy: custom compression options for handling edge cases.

Allows overriding every option for:

- compression
- mangle
- special *

* Special is a set of additional options specifically for exceptional cases

lib/tessel/deploy-lists.js

@@ -3,5 +3,30 @@ module.exports = {
     'negotiator/**/*.js',
     'socket.io-client/socket.io.js',
     'mime/types/*.types'
-  ]
+  ],
+  compressionOptions: {
+    'extend': {
+      special: {
+        /*
+          The "extend" module uses the following unadvisable pattern:
+
+          module.exports = function NAME() {
+            ... later calls NAME()
+          };
+
+          UglifyJS's compression algorithm wants to remove that unnecessary
+          function expression _name_. That's ok, because we can just as
+          easily use `keep_fnames: true` to avoid that removal. Unfortunately,
+          that's not enough in this case, as mangling produces sometimes
+          requires another pass with `figure_out_scope` to avoid
+          unhygienic mangling.
+        */
+        rescope_after_mangle: true
+      },
+      compress: {
+        keep_fnames: true
+      },
+      mangle: {}
+    },
+  },
 };

lib/tessel/deploy.js

@@ -785,14 +785,15 @@ actions.tarBundle = function(opts) {
             var isJS = dependency.file.endsWith('.js');
             var source = dependency.source;
             var target = path.normalize(dependency.file.replace(absRoot, tempBundleDir));
+            var compressionOptions = deployLists.compressionOptions[dependency.packageName];
 
             if (opts.single && !dependency.entry) {
               return;
             }
 
             if (isJS) {
               try {
-                source = actions.compress(source);
+                source = actions.compress(source, compressionOptions);
               } catch (error) {
                 reject(error);
               }
@@ -996,14 +997,49 @@ actions.project = function(options) {
   return new Project(options);
 };
 
-actions.compress = function(source) {
+actions.compress = function(source, options) {
   source = typeof source === 'string' ? source : source.toString();
 
+  options = options || {
+    compress: {},
+    mangle: {},
+    special: {},
+  };
+
+  var compress = {
+    // ------
+    booleans: true,
+    cascade: true,
+    conditionals: true,
+    comparisons: true,
+    evaluate: true,
+    hoist_funs: true,
+    hoist_vars: true,
+    if_return: true,
+    join_vars: true,
+    loops: true,
+    properties: true,
+    screw_ie8: true,
+    sequences: true,
+    unsafe: true,
+    // ------
+    keep_fargs: false,
+    keep_fnames: false,
+    warnings: false,
+    drop_console: false,
+  };
   var mangle = {
     sort: true,
-    toplevel: true
+    toplevel: true,
+  };
+  var special = {
+    rescope_after_mangle: false,
   };
 
+  Object.assign(compress, options.compress || {});
+  Object.assign(mangle, options.mangle || {});
+  Object.assign(special, options.special || {});
+
   var ast;
 
   try {
@@ -1044,33 +1080,16 @@ actions.compress = function(source) {
   // really shouldn't be our problem, but it happens.
   try {
     ast.figure_out_scope();
-    ast = ast.transform(uglify.Compressor({
-      // ------
-      booleans: true,
-      cascade: true,
-      conditionals: true,
-      comparisons: true,
-      evaluate: true,
-      hoist_funs: true,
-      hoist_vars: true,
-      if_return: true,
-      join_vars: true,
-      loops: true,
-      properties: true,
-      screw_ie8: true,
-      sequences: true,
-      unsafe: true,
-      // ------
-      keep_fargs: false,
-      keep_fnames: false,
-      warnings: false,
-      drop_console: false,
-    }));
+    ast = ast.transform(uglify.Compressor(compress));
 
     ast.figure_out_scope(mangle);
     ast.compute_char_frequency(mangle);
     ast.mangle_names(mangle);
 
+    if (special.rescope_after_mangle) {
+      ast.figure_out_scope(mangle);
+    }
+
     var stream = uglify.OutputStream();
 
     ast.print(stream);

package.json

@@ -69,7 +69,7 @@
     "ssh2": "^0.4.2",
     "sshpk": "^1.6.0",
     "stream-to-buffer": "^0.1.0",
-    "t2-project": "^0.0.6",
+    "t2-project": "^0.1.0",
     "tar": "^2.1.1",
     "tar-stream": "^1.3.0",
     "uglify-js": "^2.5.0",

test/unit/deploy-lists.js

@@ -20,5 +20,31 @@ exports['deploy-lists'] = {
 
     test.deepEqual(deployLists.includes, includes);
     test.done();
+  },
+
+  checkCompression: function(test) {
+    test.expect(1);
+
+    /*
+      This test just ensures that no one accidentally
+      messes up the contents of the deploy-lists file,
+      specifically for the compression options field
+
+     */
+    var compressionOptions = {
+      extend: {
+        special: {
+          rescope_after_mangle: true
+        },
+        compress: {
+          keep_fnames: true
+        },
+        mangle: {}
+      },
+    };
+
+    test.deepEqual(deployLists.compressionOptions, compressionOptions);
+    test.done();
   }
+
 };

test/unit/deploy.js

@@ -517,6 +517,46 @@ exports['deploy.compress'] = {
     test.done();
   },
 
+  theirCompressorOptions: function(test) {
+    test.expect(18);
+
+    var theirExplicitSettings = {
+      // ------
+      booleans: false,
+      cascade: false,
+      conditionals: false,
+      comparisons: false,
+      evaluate: false,
+      hoist_funs: false,
+      hoist_vars: false,
+      if_return: false,
+      join_vars: false,
+      loops: false,
+      properties: false,
+      screw_ie8: false,
+      sequences: false,
+      unsafe: false,
+      // ------
+      keep_fargs: true,
+      keep_fnames: true,
+      warnings: true,
+      drop_console: true,
+    };
+
+    var theirExplicitSettingsKeys = Object.keys(theirExplicitSettings);
+
+    deploy.compress('var a = 1;', {
+      compress: theirExplicitSettings
+    });
+
+    var optionsSeen = this.Compressor.lastCall.args[0];
+
+    theirExplicitSettingsKeys.forEach(key => {
+      test.equal(optionsSeen[key], theirExplicitSettings[key]);
+    });
+
+    test.done();
+  },
   minifyFromBuffer: function(test) {
     test.expect(1);
     test.equal(deploy.compress(new Buffer(codeContents)), codeContents);