microoptimizations

lib/6to5/transformation/transform.js

@@ -81,8 +81,8 @@ _.each({
   _declarations:             require("./transformers/_declarations"),
 
   // spec
-  specPropertyLiterals:        require("./transformers/spec-property-literals"),
-  specMemberExpressioLiterals: require("./transformers/spec-member-expression-literals"),
+  specPropertyLiterals:         require("./transformers/spec-property-literals"),
+  specMemberExpressionLiterals: require("./transformers/spec-member-expression-literals"),
 
   // wrap up
   _aliasFunctions:           require("./transformers/_alias-functions"),

lib/6to5/transformation/transformer.js

@@ -18,6 +18,13 @@ Transformer.normalise = function (transformer) {
     if (type[0] === "_") return;
     if (_.isFunction(fns)) fns = { enter: fns };
     transformer[type] = fns;
+
+    var aliases = t.FLIPPED_ALIAS_KEYS[type];
+    if (aliases) {
+      _.each(aliases, function (alias) {
+        transformer[alias] = fns;
+      });
+    }
   });
 
   return transformer;
@@ -42,16 +49,7 @@ Transformer.prototype.transform = function (file) {
 
   var build = function (exit) {
     return function (node, parent, scope) {
-      // add any node type aliases that exist
-      var types = [node.type].concat(t.ALIAS_KEYS[node.type] || []);
-
-      var fns = transformer.all;
-
-      _.each(types, function (type) {
-        fns = transformer[type] || fns;
-      });
-
-      // this transformer cannot deal with this node type
+      var fns = transformer[node.type];
       if (!fns) return;
 
       var fn = fns.enter;

lib/6to5/transformation/transformers/_declarations.js

@@ -1,11 +1,12 @@
 var t = require("../../types");
-var _ = require("lodash");
 
 exports.BlockStatement =
 exports.Program = function (node) {
   var kinds = {};
 
-  _.each(node._declarations, function (declar) {
+  for (var i in node._declarations) {
+    var declar = node._declarations[i];
+
     var kind = declar.kind || "var";
     var declarNode = t.variableDeclarator(declar.id, declar.init);
 
@@ -15,9 +16,9 @@ exports.Program = function (node) {
     } else {
       node.body.unshift(t.variableDeclaration(kind, [declarNode]));
     }
-  });
+  }
 
-  _.each(kinds, function (declars, kind) {
-    node.body.unshift(t.variableDeclaration(kind, declars));
-  });
+  for (var kind in kinds) {
+    node.body.unshift(t.variableDeclaration(kind, kinds[kind]));
+  }
 };

lib/6to5/transformation/transformers/es5-property-method-assignment.js

@@ -1,5 +1,4 @@
 var util = require("../../util");
-var _    = require("lodash");
 
 exports.Property = function (node) {
   if (node.method) node.method = false;
@@ -7,9 +6,11 @@ exports.Property = function (node) {
 
 exports.ObjectExpression = function (node, parent, file) {
   var mutatorMap = {};
+  var hasAny = false;
 
   node.properties = node.properties.filter(function (prop) {
     if (prop.kind === "get" || prop.kind === "set") {
+      hasAny = true;
       util.pushMutatorMap(mutatorMap, prop.key, prop.kind, prop.value);
       return false;
     } else {
@@ -17,7 +18,7 @@ exports.ObjectExpression = function (node, parent, file) {
     }
   });
 
-  if (_.isEmpty(mutatorMap)) return;
+  if (!hasAny) return;
 
   var objId = util.getUid(parent, file);
 

lib/6to5/transformation/transformers/es6-classes.js

@@ -1,7 +1,6 @@
 var traverse = require("../../traverse");
 var util     = require("../../util");
 var t        = require("../../types");
-var _        = require("lodash");
 
 exports.ClassDeclaration = function (node, parent, file, scope) {
   return new Class(node, file, scope, false).run();
@@ -26,6 +25,9 @@ function Class(node, file, scope, closure) {
   this.node    = node;
   this.file    = file;
 
+  this.hasInstanceMutators = false;
+  this.hasStaticMutators   = false;
+
   this.instanceMutatorMap = {};
   this.staticMutatorMap   = {};
   this.hasConstructor     = false;
@@ -108,7 +110,8 @@ Class.prototype.buildBody = function () {
   var body        = this.body;
   var self        = this;
 
-  _.each(classBody, function (node) {
+  for (var i in classBody) {
+    var node = classBody[i];
     if (t.isMethodDefinition(node)) {
       self.replaceInstanceSuperReferences(node);
 
@@ -121,7 +124,7 @@ Class.prototype.buildBody = function () {
       self.closure = true;
       body.unshift(node);
     }
-  });
+  }
 
   if (!this.hasConstructor && superName) {
     constructor.body.body.push(util.template("class-super-constructor-call", {
@@ -132,7 +135,7 @@ Class.prototype.buildBody = function () {
   var instanceProps;
   var staticProps;
 
-  if (!_.isEmpty(this.instanceMutatorMap)) {
+  if (this.hasInstanceMutators) {
     var protoId = util.template("prototype-identifier", {
       CLASS_NAME: className
     });
@@ -140,7 +143,7 @@ Class.prototype.buildBody = function () {
     instanceProps = util.buildDefineProperties(this.instanceMutatorMap, protoId);
   }
 
-  if (!_.isEmpty(this.staticMutatorMap)) {
+  if (this.hasStaticMutators) {
     staticProps = util.buildDefineProperties(this.staticMutatorMap, className);
   }
 
@@ -174,11 +177,18 @@ Class.prototype.pushMethod = function (node) {
     if (!node.static) className = t.memberExpression(className, t.identifier("prototype"));
     methodName = t.memberExpression(className, methodName, node.computed);
 
-    this.body.push(t.expressionStatement(t.assignmentExpression("=", methodName, node.value)));
+    var expr = t.expressionStatement(t.assignmentExpression("=", methodName, node.value));
+    t.inheritsComments(expr, node);
+    this.body.push(expr);
   } else {
     // mutator
     var mutatorMap = this.instanceMutatorMap;
-    if (node.static) mutatorMap = this.staticMutatorMap;
+    if (node.static) {
+      this.hasStaticMutators = true;
+      mutatorMap = this.staticMutatorMap;
+    } else {
+      this.hasInstanceMutators = true;
+    }
     util.pushMutatorMap(mutatorMap, methodName, kind, node);
   }
 };
@@ -265,6 +275,7 @@ Class.prototype.pushConstructor = function (method) {
   var fn        = method.value;
 
   this.hasConstructor = true;
+
   t.inherits(construct, fn);
   t.inheritsComments(construct, method);
 

lib/6to5/transformation/transformers/es6-computed-property-names.js

@@ -1,6 +1,5 @@
 var util = require("../../util");
 var t    = require("../../types");
-var _    = require("lodash");
 
 exports.ObjectExpression = function (node, parent, file) {
   var hasComputed = false;
@@ -31,7 +30,8 @@ exports.ObjectExpression = function (node, parent, file) {
 
   containerCallee._aliasFunction = true;
 
-  _.each(computed, function (prop) {
+  for (var i in computed) {
+    var prop = computed[i];
     containerBody.unshift(
       t.expressionStatement(
         t.assignmentExpression(
@@ -41,7 +41,7 @@ exports.ObjectExpression = function (node, parent, file) {
         )
       )
     );
-  });
+  }
 
   return container;
 };

lib/6to5/transformation/transformers/es6-constants.js

@@ -7,6 +7,7 @@ exports.BlockStatement =
 exports.ForInStatement =
 exports.ForOfStatement =
 exports.ForStatement = function (node, parent, file) {
+  var hasConstants = false;
   var constants = {};
 
   /**
@@ -15,17 +16,18 @@ exports.ForStatement = function (node, parent, file) {
    */
 
   var check = function (parent, names, scope) {
-    _.each(names, function (nameNode, name) {
-      if (!_.has(constants, name)) return;
-      if (parent && t.isBlockStatement(parent) && parent !== constants[name]) return;
+    for (var name in names) {
+      var nameNode = names[name];
+      if (!_.has(constants, name)) continue;
+      if (parent && t.isBlockStatement(parent) && parent !== constants[name]) continue;
 
       if (scope) {
         var defined = scope.get(name);
-        if (defined && defined === nameNode) return;
+        if (defined && defined === nameNode) continue;
       }
 
       throw file.errorWithNode(nameNode, name + " is read-only");
-    });
+    }
   };
 
   var getIds = function (node) {
@@ -38,24 +40,30 @@ exports.ForStatement = function (node, parent, file) {
 
   _.each(node.body, function (child, parent) {
     if (child && t.isVariableDeclaration(child, { kind: "const" })) {
-      _.each(child.declarations, function (declar) {
-        _.each(getIds(declar), function (nameNode, name) {
+      for (var i in child.declarations) {
+        var declar = child.declarations[i];
+
+        var ids = getIds(declar);
+        for (var name in ids) {
+          var nameNode = ids[name];
+
           var names = {};
           names[name] = nameNode;
           check(parent, names);
 
           constants[name] = parent;
-        });
+          hasConstants = true;
+        }
 
         declar._ignoreConstant = true;
-      });
+      }
 
       child._ignoreConstant = true;
       child.kind = "let";
     }
   });
 
-  if (_.isEmpty(constants)) return;
+  if (!hasConstants) return;
 
   traverse(node, function (child, parent, scope) {
     if (child._ignoreConstant) return;

lib/6to5/transformation/transformers/es6-default-parameters.js

@@ -1,4 +1,5 @@
 var traverse = require("../../traverse");
+var Scope    = require("../../traverse/scope");
 var util     = require("../../util");
 var t        = require("../../types");
 var _        = require("lodash");
@@ -13,8 +14,9 @@ exports.Function = function (node, parent, file, scope) {
 
   var iife = false;
 
-  _.each(node.defaults, function (def, i) {
-    if (!def) return;
+  for (var i in node.defaults) {
+    var def = node.defaults[i];
+    if (!def) continue;
 
     var param = node.params[i];
 
@@ -42,18 +44,19 @@ exports.Function = function (node, parent, file, scope) {
     if (has && !_.contains(node.params, has)) {
       iife = true;
     }
-  });
+  }
 
   var body = [];
 
-  _.each(node.defaults, function (def, i) {
-    if (!def) return;
+  for (var i in node.defaults) {
+    var def = node.defaults[i];
+    if (!def) continue;
 
     body.push(util.template("if-undefined-set-to", {
       VARIABLE: node.params[i],
       DEFAULT:  def
     }, true));
-  });
+  }
 
   if (iife) {
     var container = t.functionExpression(null, [], node.body, node.generator);

lib/6to5/transformation/transformers/es6-destructuring.js

@@ -1,7 +1,6 @@
 // TODO: Clean up
 
 var t = require("../../types");
-var _ = require("lodash");
 
 var buildVariableAssign = function (opts, id, init) {
   var op = opts.operator;
@@ -27,20 +26,23 @@ var push = function (opts, nodes, elem, parentId) {
 };
 
 var pushObjectPattern = function (opts, nodes, pattern, parentId) {
-  _.each(pattern.properties, function (prop, i) {
+  for (var i in pattern.properties) {
+    var prop = pattern.properties[i];
     if (t.isSpreadProperty(prop)) {
         // get all the keys that appear in this object before the current spread
         var keys = [];
-        _.each(pattern.properties, function (prop2, i2) {
-          if (i2 >= i) return false;
-          if (t.isSpreadProperty(prop2)) return;
+        for (var i2 in pattern.properties) {
+          var prop2 = pattern.properties[i2];
+
+          if (i2 >= i) break;
+          if (t.isSpreadProperty(prop2)) continue;
 
           var key = prop2.key;
           if (t.isIdentifier(key)) {
             key = t.literal(prop2.key.name);
           }
           keys.push(key);
-        });
+        }
         keys = t.arrayExpression(keys);
 
         var value = t.callExpression(opts.file.addDeclaration("object-spread"), [parentId, keys]);
@@ -55,7 +57,7 @@ var pushObjectPattern = function (opts, nodes, pattern, parentId) {
         nodes.push(buildVariableAssign(opts, pattern2, patternId2));
       }
     }
-  });
+  }
 };
 
 var pushArrayPattern = function (opts, nodes, pattern, parentId) {
@@ -65,15 +67,18 @@ var pushArrayPattern = function (opts, nodes, pattern, parentId) {
   ]));
   parentId = _parentId;
 
-  _.each(pattern.elements, function (elem, i) {
-    if (!elem) return;
+  for (var i in pattern.elements) {
+    var elem = pattern.elements[i];
+    if (!elem) continue;
+
+    i = +i;
 
     var newPatternId;
 
     if (t.isSpreadElement(elem)) {
       newPatternId = opts.file.toArray(parentId);
 
-      if (+i > 0) {
+      if (i > 0) {
         newPatternId = t.callExpression(t.memberExpression(newPatternId, t.identifier("slice")), [t.literal(i)]);
       }
 
@@ -83,7 +88,7 @@ var pushArrayPattern = function (opts, nodes, pattern, parentId) {
     }
 
     push(opts, nodes, elem, newPatternId);
-  });
+  }
 };
 
 var pushPattern = function (opts) {
@@ -217,15 +222,18 @@ exports.VariableDeclaration = function (node, parent, file, scope) {
   var nodes = [];
 
   var hasPattern = false;
-  _.each(node.declarations, function (declar) {
+  for (var i in node.declarations) {
+    var declar = node.declarations[i];
     if (t.isPattern(declar.id)) {
       hasPattern = true;
-      return false;
+      break;
     }
-  });
+  }
   if (!hasPattern) return;
 
-  _.each(node.declarations, function (declar) {
+  for (var i in node.declarations) {
+    var declar = node.declarations[i];
+
     var patternId = declar.init;
     var pattern   = declar.id;
     var opts = {
@@ -241,12 +249,13 @@ exports.VariableDeclaration = function (node, parent, file, scope) {
     } else {
       nodes.push(buildVariableAssign(opts, declar.id, declar.init));
     }
-  });
+  }
 
   if (!t.isProgram(parent) && !t.isBlockStatement(parent)) {
     var declar;
 
-    _.each(nodes, function (node) {
+    for (var i in nodes) {
+      var node = nodes[i];
       declar = declar || t.variableDeclaration(node.kind, []);
 
       if (!t.isVariableDeclaration(node) && declar.kind !== node.kind) {
@@ -254,7 +263,7 @@ exports.VariableDeclaration = function (node, parent, file, scope) {
       }
 
       declar.declarations = declar.declarations.concat(node.declarations);
-    });
+    }
 
     return declar;
   }

lib/6to5/transformation/transformers/es6-generators/index.js

@@ -1 +1,3 @@
-module.exports = require("./visit").transform;
+var t = require("../../../types");
+
+exports.ast = require("./visit").transform;

lib/6to5/transformation/transformers/es6-let-scoping.js

@@ -18,9 +18,9 @@ var isVar = function (node) {
 };
 
 var standardiseLets = function (declars) {
-  _.each(declars, function (declar) {
-    delete declar._let;
-  });
+  for (var i in declars) {
+    delete declars[i]._let;
+  }
 };
 
 exports.VariableDeclaration = function (node) {
@@ -160,8 +160,9 @@ LetScoping.prototype.noClosure = function () {
 LetScoping.prototype.remap = function () {
   var replacements = this.info.duplicates;
   var block        = this.block;
+  var file         = this.file;
 
-  if (_.isEmpty(replacements)) return;
+  if (!this.info.hasDuplicates) return;
 
   var replace = function (node, parent, scope) {
     if (!t.isIdentifier(node)) return;
@@ -209,6 +210,8 @@ LetScoping.prototype.getInfo = function () {
     // all references with it
     duplicates:  {},
 
+    hasDuplicates: false,
+
     // array of `Identifier` names of let variables that are accessible within
     // the current block
     keys:        []
@@ -221,28 +224,31 @@ LetScoping.prototype.getInfo = function () {
       // there's a variable with this exact name in an upper scope so we need
       // to generate a new name
       opts.duplicates[key] = id.name = file.generateUid(key, scope);
+      opts.hasDuplicates = true;
     }
   };
 
-  _.each(opts.declarators, function (declar) {
+  for (var i in opts.declarators) {
+    var declar = opts.declarators[i];
     opts.declarators.push(declar);
 
     var keys = t.getIds(declar, true);
     _.each(keys, duplicates);
-    keys = _.keys(keys);
+    keys = Object.keys(keys);
 
     opts.outsideKeys = opts.outsideKeys.concat(keys);
     opts.keys = opts.keys.concat(keys);
-  });
+  }
 
-  _.each(block.body, function (declar) {
-    if (!isLet(declar)) return;
+  for (var i in block.body) {
+    var declar = block.body[i];
+    if (!isLet(declar)) continue;
 
     _.each(t.getIds(declar, true), function (id, key) {
       duplicates(id, key);
       opts.keys.push(key);
     });
-  });
+  }
 
   return opts;
 };
@@ -417,12 +423,13 @@ LetScoping.prototype.pushDeclar = function (node) {
 
   var replace = [];
 
-  _.each(node.declarations, function (declar) {
-    if (!declar.init) return;
+  for (var i in node.declarations) {
+    var declar = node.declarations[i];
+    if (!declar.init) continue;
 
     var expr = t.assignmentExpression("=", declar.id, declar.init);
     replace.push(t.inherits(expr, declar));
-  });
+  }
 
   return replace;
 };

lib/6to5/transformation/transformers/es6-modules.js

@@ -1,5 +1,4 @@
 var t = require("../../types");
-var _ = require("lodash");
 
 var inheritsComments = function (node, nodes) {
   if (nodes.length) {
@@ -11,9 +10,9 @@ exports.ImportDeclaration = function (node, parent, file) {
   var nodes = [];
 
   if (node.specifiers.length) {
-    _.each(node.specifiers, function (specifier) {
-      file.moduleFormatter.importSpecifier(specifier, node, nodes, parent);
-    });
+    for (var i in node.specifiers) {
+      file.moduleFormatter.importSpecifier(node.specifiers[i], node, nodes, parent);
+    }
   } else {
     file.moduleFormatter.import(node, nodes, parent);
   }
@@ -36,9 +35,9 @@ exports.ExportDeclaration = function (node, parent, file) {
 
     file.moduleFormatter.export(node, nodes, parent);
   } else {
-    _.each(node.specifiers, function (specifier) {
-      file.moduleFormatter.exportSpecifier(specifier, node, nodes, parent);
-    });
+    for (var i in node.specifiers) {
+      file.moduleFormatter.exportSpecifier(node.specifiers[i], node, nodes, parent);
+    }
   }
 
   inheritsComments(node, nodes);

lib/6to5/transformation/transformers/es6-spread.js

@@ -1,19 +1,16 @@
 var t = require("../../types");
-var _ = require("lodash");
 
 var getSpreadLiteral = function (spread, file) {
   return file.toArray(spread.argument);
 };
 
 var hasSpread = function (nodes) {
-  var has = false;
-  _.each(nodes, function (node) {
-    if (t.isSpreadElement(node)) {
-      has = true;
-      return false;
+  for (var i in nodes) {
+    if (t.isSpreadElement(nodes[i])) {
+      return true;
     }
-  });
-  return has;
+  }
+  return false;
 };
 
 var build = function (props, file) {
@@ -27,14 +24,15 @@ var build = function (props, file) {
     _props = [];
   };
 
-  _.each(props, function (prop) {
+  for (var i in props) {
+    var prop = props[i];
     if (t.isSpreadElement(prop)) {
       push();
       nodes.push(getSpreadLiteral(prop, file));
     } else {
       _props.push(prop);
     }
-  });
+  }
 
   push();
 

lib/6to5/transformation/transformers/es6-template-literals.js

@@ -1,5 +1,4 @@
 var t = require("../../types");
-var _ = require("lodash");
 
 var buildBinaryExpression = function (left, right) {
   return t.binaryExpression("+", left, right);
@@ -12,10 +11,11 @@ exports.TaggedTemplateExpression = function (node, parent, file) {
   var strings = [];
   var raw = [];
 
-  _.each(quasi.quasis, function (elem) {
+  for (var i in quasi.quasis) {
+    var elem = quasi.quasis[i];
     strings.push(t.literal(elem.value.cooked));
     raw.push(t.literal(elem.value.raw));
-  });
+  }
 
   args.push(t.callExpression(file.addDeclaration("tagged-template-literal"), [
     t.arrayExpression(strings),
@@ -30,7 +30,9 @@ exports.TaggedTemplateExpression = function (node, parent, file) {
 exports.TemplateLiteral = function (node) {
   var nodes = [];
 
-  _.each(node.quasis, function (elem) {
+  for (var i in node.quasis) {
+    var elem = node.quasis[i];
+
     nodes.push(t.literal(elem.value.cooked));
 
     var expr = node.expressions.shift();
@@ -38,18 +40,18 @@ exports.TemplateLiteral = function (node) {
       if (t.isBinary(expr)) expr = t.parenthesizedExpression(expr);
       nodes.push(expr);
     }
-  });
+  }
 
   if (nodes.length > 1) {
     // remove redundant '' at the end of the expression
-    var last = _.last(nodes);
+    var last = nodes[nodes.length - 1];
     if (t.isLiteral(last, { value: "" })) nodes.pop();
 
     var root = buildBinaryExpression(nodes.shift(), nodes.shift());
 
-    _.each(nodes, function (node) {
-      root = buildBinaryExpression(root, node);
-    });
+    for (var i in nodes) {
+      root = buildBinaryExpression(root, nodes[i]);
+    }
 
     return root;
   } else {

lib/6to5/transformation/transformers/es6-unicode-regex.js

@@ -6,7 +6,7 @@ exports.Literal = function (node) {
   if (!regex) return;
 
   var flags = regex.flags.split("");
-  if (!_.contains(regex.flags, "u")) return;
+  if (regex.flags.indexOf("u") < 0) return;
   _.pull(flags, "u");
 
   regex.pattern = rewritePattern(regex.pattern, regex.flags);

lib/6to5/transformation/transformers/es7-array-comprehension.js

@@ -1,6 +1,5 @@
 var util = require("../../util");
 var t    = require("../../types");
-var _    = require("lodash");
 
 var single = function (node, file) {
   var block = node.blocks[0];
@@ -15,11 +14,13 @@ var single = function (node, file) {
     KEY:       block.left
   });
 
-  _.each([result.callee.object, result], function (call) {
+  var aliasPossibles = [result.callee.object, result];
+  for (var i in aliasPossibles) {
+    var call = aliasPossibles[i];
     if (t.isCallExpression(call)) {
       call.arguments[0]._aliasFunction = true;
     }
-  });
+  }
 
   return result;
 };

lib/6to5/transformation/transformers/es7-object-spread.js

@@ -1,16 +1,16 @@
 // https://github.com/sebmarkbage/ecmascript-rest-spread
 
 var t = require("../../types");
-var _ = require("lodash");
 
 exports.ObjectExpression = function (node) {
   var hasSpread = false;
-  _.each(node.properties, function (prop) {
+  for (var i in node.properties) {
+    var prop = node.properties[i];
     if (t.isSpreadProperty(prop)) {
       hasSpread = true;
-      return false;
+      break;
     }
-  });
+  }
   if (!hasSpread) return;
 
   var args = [];
@@ -22,14 +22,15 @@ exports.ObjectExpression = function (node) {
     props = [];
   };
 
-  _.each(node.properties, function (prop) {
+  for (var i in node.properties) {
+    var prop = node.properties[i];
     if (t.isSpreadProperty(prop)) {
       push();
       args.push(prop.argument);
     } else {
       props.push(prop);
     }
-  });
+  }
 
   push();
 

lib/6to5/transformation/transformers/react.js

@@ -5,7 +5,6 @@
 
 var esutils = require("esutils");
 var t       = require("../../types");
-var _       = require("lodash");
 
 exports.XJSIdentifier = function (node) {
   if (esutils.keyword.isIdentifierName(node.name)) {
@@ -49,7 +48,7 @@ exports.XJSOpeningElement = {
       tagName = tagExpr.value;
     }
 
-    if (tagName && (/[a-z]/.exec(tagName[0]) || _.contains(tagName, "-"))) {
+    if (tagName && (/[a-z]/.exec(tagName[0]) || tagName.indexOf("-") >= 0)) {
       args.push(t.literal(tagName));
     } else {
       args.push(tagExpr);
@@ -106,13 +105,17 @@ exports.XJSElement = {
   exit: function (node) {
     var callExpr = node.openingElement;
 
-    _.each(node.children, function (child) {
+    for (var i in node.children) {
+      var child = node.children[i];
+
       if (t.isLiteral(child)) {
         var lines = child.value.split(/\r\n|\n|\r/);
 
-        _.each(lines, function (line, i) {
-          var isFirstLine = i === 0;
-          var isLastLine = i === lines.length - 1;
+        for (var i in lines) {
+          var line = lines[i];
+
+          var isFirstLine = i == 0;
+          var isLastLine = i == lines.length - 1;
 
           // replace rendered whitespace tabs with spaces
           var trimmedLine = line.replace(/\t/g, ' ');
@@ -130,15 +133,15 @@ exports.XJSElement = {
           if (trimmedLine) {
             callExpr.arguments.push(t.literal(trimmedLine));
           }
-        });
+        }
 
-        return;
+        continue;
       } else if (t.isXJSEmptyExpression(child)) {
-        return;
+        continue;
       }
 
       callExpr.arguments.push(child);
-    });
+    }
 
     return t.inherits(callExpr, node);
   }
@@ -171,11 +174,13 @@ var addDisplayName = function (id, call) {
   var props = first.properties;
   var safe = true;
 
-  _.each(props, function (prop) {
+  for (var i in props) {
+    var prop = props[i];
     if (t.isIdentifier(prop.key, { name: "displayName" })) {
-      return safe = false;
+      safe = false;
+      break;
     }
-  });
+  }
 
   if (safe) {
     props.unshift(t.property("init", t.identifier("displayName"), t.literal(id)));

lib/6to5/transformation/transformers/spec-no-duplicate-properties.js

@@ -1,11 +1,11 @@
 var t = require("../../types");
-var _ = require("lodash");
 
 exports.ObjectExpression = function (node, parent, file) {
   var keys = [];
 
-  _.each(node.properties, function (prop) {
-    if (prop.computed || prop.kind !== "init") return;
+  for (var i in node.properties) {
+    var prop = node.properties[i];
+    if (prop.computed || prop.kind !== "init") continue;
 
     var key = prop.key;
     if (t.isIdentifier(key)) {
@@ -13,13 +13,13 @@ exports.ObjectExpression = function (node, parent, file) {
     } else if (t.isLiteral(key)) {
       key = key.value;
     } else {
-      return;
+      continue;
     }
 
-    if (_.contains(keys, key)) {
+    if (keys.indexOf(key) >= 0) {
       throw file.errorWithNode(prop.key, "Duplicate property key");
     } else {
       keys.push(key);
     }
-  });
+  }
 };

lib/6to5/types/builder-keys.json

@@ -1,5 +1,6 @@
 {
   "ArrayExpression":         ["elements"],
+  "ArrowFunctionExpression": ["params", "body"],
   "AssignmentExpression":    ["operator", "left", "right"],
   "BinaryExpression":        ["operator", "left", "right"],
   "BlockStatement":          ["body"],

lib/6to5/types/index.js

@@ -45,20 +45,20 @@ _.each(t.BUILDER_KEYS, function (keys, type) {
 
 t.ALIAS_KEYS = require("./alias-keys");
 
-var _aliases = {};
+t.FLIPPED_ALIAS_KEYS = {};
 
 _.each(t.ALIAS_KEYS, function (aliases, type) {
   _.each(aliases, function (alias) {
-    var types = _aliases[alias] = _aliases[alias] || [];
+    var types = t.FLIPPED_ALIAS_KEYS[alias] = t.FLIPPED_ALIAS_KEYS[alias] || [];
     types.push(type);
   });
 });
 
-_.each(_aliases, function (types, type) {
+_.each(t.FLIPPED_ALIAS_KEYS, function (types, type) {
   t[type.toUpperCase() + "_TYPES"] = types;
 
   var is = t["is" + type] = function (node, opts) {
-    return node && _.contains(types, node.type) && t.shallowEqual(node, opts);
+    return node && types.indexOf(node.type) >= 0 && t.shallowEqual(node, opts);
   };
 
   addAssert(type, is);