switch from escodegen to recast which is slower but far superior

README.md

@@ -151,11 +151,7 @@ to5.transformFile("filename.js", options, function (err, result) {
   sourceMap: false,
 
   // Filename for use in errors etc.
-  filename: "unknown",
-
-  // Format options
-  // See https://github.com/Constellation/escodegen/wiki/API for options.
-  format: {}
+  filename: "unknown"
 }
 ```
 

bin/generate-browser-test

@@ -1,5 +1,6 @@
 #!/usr/bin/env node
 
 var helper = require("../test/_helper");
+var util   = require("../test/_helper");
 
-console.log("(" + helper.run + ")(" + JSON.stringify(helper.getTests(), null, "  ") + ", to5, proclaim)");
+console.log("(" + helper.run + ")(" + util.formatJSON(helper.getTests()) + ", to5, proclaim)");

lib/6to5/transform.js

@@ -1,5 +1,6 @@
 var traverse = require("./traverse");
 var assert   = require("assert");
+var recast   = require("recast");
 var path     = require("path");
 var util     = require("./util");
 var _        = require("lodash");
@@ -51,28 +52,13 @@ transform._run = function (code, tree, opts) {
     transform._runTransformer(transformer, tree, opts, generateUid);
   });
 
-  var genOpts = {
-    file: path.basename(opts.filename),
-    format: opts.format
-  };
+  var result = util.generate(tree, opts);
 
-  if (opts.sourceMap) {
-    genOpts.sourceMap = genOpts.file;
-    genOpts.sourceContent = code;
-    genOpts.sourceMapWithCode = true;
+  if (opts.sourceMap === "inline") {
+    result.code += "\n" + util.sourceMapToComment(result.map);
   }
 
-  var result = util.generate(tree, genOpts);
-
-  if (opts.sourceMap) {
-    if (opts.sourceMap === "inline") {
-      result.code += "\n" + util.sourceMapToComment(result.map);
-    }
-
-    return result;
-  } else {
-    return { code: result, map: null };
-  }
+  return result;
 };
 
 transform._runTransformer = function (transformer, tree, opts, generateUid) {
@@ -86,20 +72,32 @@ transform._runTransformer = function (transformer, tree, opts, generateUid) {
   });
 };
 
-transform.test = function (actual, expect, opts) {
-  opts = opts || {};
-  _.defaults(opts, { filename: "test" });
+transform.test = function (task, assert) {
+  var actual = task.actual;
+  var expect = task.expect;
+  var opts   = task.options;
+
+  opts.filename = actual.filename;
 
   var actualCode = actual.code.trim();
-  var transformedCode = transform(actualCode, opts).code;
+
+  var transformedResult = transform(actualCode, opts);
+  var transformedCode = transformedResult.code;
+
   var actualAst = util.parse(actual.filename, transformedCode);
-  actualCode = util.generate(actualAst);
+  var actualResult = recast.prettyPrint(actualAst);
+  actualCode = actualResult.code;
 
   var expectCode = expect.code.trim();
   var expectAst = util.parse(expect.filename, expectCode);
-  expectCode = util.generate(expectAst);
+  var expectResult = recast.prettyPrint(expectAst);
+  expectCode = expectResult.code;
 
   assert.equal(actualCode, expectCode);
+
+  if (opts.sourceMap && task.sourceMap) {
+    assert.deepEqual(util.formatJSON(transformedResult.map), util.formatJSON(task.sourceMap));
+  }
 };
 
 transform.transformers = {

lib/6to5/traverse/visitor-keys.json

@@ -3,6 +3,7 @@
   "ArrayPattern":                  ["elements"],
   "ArrowFunctionExpression":       ["params", "defaults", "rest", "body"],
   "AssignmentExpression":          ["left", "right"],
+  "AwaitExpression":               ["argument"],
   "BinaryExpression":              ["left", "right"],
   "BlockStatement":                ["body"],
   "BreakStatement":                ["label"],
@@ -23,6 +24,7 @@
   "ExportBatchSpecifier":          [],
   "ExportSpecifier":               ["id", "name"],
   "ExpressionStatement":           ["expression"],
+  "File":                          ["program"],
   "ForInStatement":                ["left", "right", "body"],
   "ForOfStatement":                ["left", "right", "body"],
   "ForStatement":                  ["init", "test", "update", "body"],
@@ -70,6 +72,5 @@
   "VoidTypeAnnotation":            [],
   "WhileStatement":                ["test", "body"],
   "WithStatement":                 ["object", "body"],
-  "YieldExpression":               ["argument"],
-  "AwaitExpression":               ["argument"]
+  "YieldExpression":               ["argument"]
 }

lib/6to5/util.js

@@ -1,46 +1,12 @@
 var estraverse = require("estraverse");
-var escodegen  = require("escodegen");
 var traverse   = require("./traverse");
 var esprima    = require("esprima-fb");
+var recast     = require("recast");
 var path       = require("path");
 var fs         = require("fs");
 var _          = require("lodash");
 var b          = require("ast-types").builders;
 
-_.each(esprima.Syntax, function (name) {
-  estraverse.VisitorKeys[name] = estraverse.VisitorKeys[name] || [];
-});
-
-exports.parse = function (filename, code, callback, opts) {
-  try {
-    var ast = esprima.parse(code, _.extend(opts || {}, {
-      comment: true,
-      source:  filename,
-      tokens:  true,
-      range:   true,
-      loc:     true
-    }));
-
-    estraverse.attachComments(ast, ast.comments, ast.tokens);
-
-    if (callback) {
-      return callback(ast);
-    } else {
-      return ast;
-    }
-  } catch (err) {
-    if (!err._6to5) {
-      err._6to5 = true;
-      err.message = filename + ": " + err.message;
-      if (err.lineNumber) {
-        var frame = exports.codeFrame(code, err.lineNumber, err.column);
-        err.message = err.message + frame;
-      }
-    }
-    throw err;
-  }
-};
-
 exports.ensureBlock = function (node) {
   var block = node.body;
   if (block.type === "BlockStatement") return;
@@ -52,19 +18,8 @@ exports.isPattern = function (node) {
   return node.type === "ArrayPattern" || node.type === "ObjectPattern";
 };
 
-exports.generate = function (ast, opts) {
-  opts = opts || {};
-
-  opts = _.merge({
-    comment: true,
-    format: {
-      indent: {
-        style: "  "
-      }
-    }
-  }, opts);
-
-  return escodegen.generate(ast, opts);
+exports.formatJSON = function (obj) {
+  return JSON.stringify(obj, null, "  ");
 };
 
 exports.removeProperties = function (tree) {
@@ -138,6 +93,7 @@ exports.buildDefineProperties = function (mutatorMap, keyNode) {
     var propNode = b.property("init", b.identifier(key), mapNode);
 
     _.each(map, function (methodNode, type) {
+      methodNode = _.clone(methodNode);
       if (methodNode.type === "MethodDefinition") methodNode = methodNode.value;
       mapNode.properties.push(b.property("init", b.identifier(type), methodNode));
     });
@@ -212,6 +168,39 @@ exports.repeat = function (width, cha) {
   return new Array(width + 1).join(cha);
 };
 
+exports.generate = function (ast, opts) {
+  var printOpts = {};
+  if (opts.sourceMap) {
+    printOpts.sourceMapName = path.basename(opts.filename);
+  }
+
+  return recast.print(ast, printOpts);
+};
+
+exports.parse = function (filename, code, callback, opts) {
+  try {
+    var ast = recast.parse(code, {
+      sourceFileName: path.basename(filename)
+    });
+
+    if (callback) {
+      return callback(ast);
+    } else {
+      return ast;
+    }
+  } catch (err) {
+    if (!err._6to5) {
+      err._6to5 = true;
+      err.message = filename + ": " + err.message;
+      if (err.lineNumber) {
+        var frame = exports.codeFrame(code, err.lineNumber, err.column);
+        err.message = err.message + frame;
+      }
+    }
+    throw err;
+  }
+};
+
 try {
   exports.templates = require("../../templates.json");
 } catch (err) {
@@ -221,7 +210,9 @@ try {
 
   var templatesLoc = __dirname + "/templates";
   if (!fs.existsSync(templatesLoc)) {
-    throw new Error("no templates directory - this is most likely the result of a broken `npm publish`. Please report to https://github.com/sebmck/6to5/issues");
+    throw new Error("no templates directory - this is most likely the result" +
+                    " of a broken `npm publish`. Please report to " +
+                    "https://github.com/sebmck/6to5/issues");
   }
 
   _.each(fs.readdirSync(templatesLoc), function (name) {
@@ -231,6 +222,6 @@ try {
 
     exports.templates[key] = exports.removeProperties(exports.parse(loc, code, null, {
       tolerant: true
-    }));
+    }).program);
   });
 }

package.json

@@ -39,15 +39,13 @@
   "dependencies": {
     "ast-types": "0.5.0",
     "commander": "2.3.0",
-    "escodegen": "https://github.com/Constellation/escodegen/archive/624550d0d6edf812a661902c6908dedff66005a7.tar.gz",
-    "esprima-fb": "7001.1.0-dev-harmony-fb",
-    "estraverse": "1.5.1",
     "fs-readdir-recursive": "0.0.2",
     "lodash": "2.4.1",
     "mkdirp": "0.5.0",
     "es6-shim": "^0.18.0",
     "es6-symbol": "^0.1.1",
-    "regexpu": "^0.2.2"
+    "regexpu": "^0.2.2",
+    "recast": "^0.8.0"
   },
   "devDependencies": {
     "es6-transpiler": "0.7.17",

test/_helper.js

@@ -20,8 +20,9 @@ exports.run = function (suites, transform, assert) {
     suite(testSuite.title, function () {
       _.each(testSuite.tests, function (task) {
         test(task.title, function () {
+
           var run = function () {
-            transform.test(task.actual, task.expect, task.options);
+            transform.test(task, assert);
           };
 
           var throwMsg = task.options.throws;
@@ -70,7 +71,8 @@ exports.getTests = function () {
       var taskOpts = _.merge({ filename: actualLoc }, _.cloneDeep(suite.options));
       if (fs.existsSync(taskOptsLoc)) _.merge(taskOpts, require(taskOptsLoc));
 
-      suite.tests.push({
+
+      var test = {
         title: humanise(taskName),
         options: taskOpts,
         actual: {
@@ -81,7 +83,15 @@ exports.getTests = function () {
           code: readFile(expectLoc),
           filename: expectLoc
         }
-      });
+      };
+
+      suite.tests.push(test);
+
+      var sourceMapLoc = taskDir + "/source-map.json";
+      if (fs.existsSync(sourceMapLoc)) {
+        test.options.sourceMap = true;
+        test.sourceMap = require(sourceMapLoc);
+      }
     });
   });