Reorganize module loading.

We now use webpack instead of SystemJS, effectively bundling modules
into one file (plus commons chunks) for every entry point.  This results
in a much smaller extension size (almost half).  Furthermore we use
yarn/npm even for extension run-time dependencies.  This relieves us
from manually vendoring and building dependencies.  It's also easier to
understand for new developers familiar with node.

14 files changed, 150 insertions, 189 deletions

diff --git a/node_modules/babel-generator/lib/buffer.js b/node_modules/babel-generator/lib/buffer.js
index 8919d2c29..40b6c2561 100644
--- a/node_modules/babel-generator/lib/buffer.js
+++ b/node_modules/babel-generator/lib/buffer.js
@@ -6,9 +6,9 @@ var _classCallCheck2 = require("babel-runtime/helpers/classCallCheck");
 
 var _classCallCheck3 = _interopRequireDefault(_classCallCheck2);
 
-var _trimEnd = require("lodash/trimEnd");
+var _trimRight = require("trim-right");
 
-var _trimEnd2 = _interopRequireDefault(_trimEnd);
+var _trimRight2 = _interopRequireDefault(_trimRight);
 
 function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
 
@@ -38,19 +38,36 @@ var Buffer = function () {
   Buffer.prototype.get = function get() {
     this._flush();
 
-    return {
-      code: (0, _trimEnd2.default)(this._buf.join("")),
-      map: this._map ? this._map.get() : null
+    var map = this._map;
+    var result = {
+      code: (0, _trimRight2.default)(this._buf.join("")),
+      map: null,
+      rawMappings: map && map.getRawMappings()
     };
+
+    if (map) {
+      Object.defineProperty(result, "map", {
+        configurable: true,
+        enumerable: true,
+        get: function get() {
+          return this.map = map.get();
+        },
+        set: function set(value) {
+          Object.defineProperty(this, "map", { value: value, writable: true });
+        }
+      });
+    }
+
+    return result;
   };
 
   Buffer.prototype.append = function append(str) {
     this._flush();
-    var _sourcePosition = this._sourcePosition;
-    var line = _sourcePosition.line;
-    var column = _sourcePosition.column;
-    var filename = _sourcePosition.filename;
-    var identifierName = _sourcePosition.identifierName;
+    var _sourcePosition = this._sourcePosition,
+        line = _sourcePosition.line,
+        column = _sourcePosition.column,
+        filename = _sourcePosition.filename,
+        identifierName = _sourcePosition.identifierName;
 
     this._append(str, line, column, identifierName, filename);
   };
@@ -58,11 +75,11 @@ var Buffer = function () {
   Buffer.prototype.queue = function queue(str) {
     if (str === "\n") while (this._queue.length > 0 && SPACES_RE.test(this._queue[0][0])) {
       this._queue.shift();
-    }var _sourcePosition2 = this._sourcePosition;
-    var line = _sourcePosition2.line;
-    var column = _sourcePosition2.column;
-    var filename = _sourcePosition2.filename;
-    var identifierName = _sourcePosition2.identifierName;
+    }var _sourcePosition2 = this._sourcePosition,
+        line = _sourcePosition2.line,
+        column = _sourcePosition2.column,
+        filename = _sourcePosition2.filename,
+        identifierName = _sourcePosition2.identifierName;
 
     this._queue.unshift([str, line, column, identifierName, filename]);
   };
diff --git a/node_modules/babel-generator/lib/generators/base.js b/node_modules/babel-generator/lib/generators/base.js
index 3be3a8a53..938022f76 100644
--- a/node_modules/babel-generator/lib/generators/base.js
+++ b/node_modules/babel-generator/lib/generators/base.js
@@ -31,11 +31,14 @@ function Program(node) {
 function BlockStatement(node) {
   this.token("{");
   this.printInnerComments(node);
-  if (node.body.length) {
+
+  var hasDirectives = node.directives && node.directives.length;
+
+  if (node.body.length || hasDirectives) {
     this.newline();
 
     this.printSequence(node.directives, node, { indent: true });
-    if (node.directives && node.directives.length) this.newline();
+    if (hasDirectives) this.newline();
 
     this.printSequence(node.body, node, { indent: true });
     this.removeTrailingNewline();
diff --git a/node_modules/babel-generator/lib/generators/expressions.js b/node_modules/babel-generator/lib/generators/expressions.js
index c6c070788..d65fa78c0 100644
--- a/node_modules/babel-generator/lib/generators/expressions.js
+++ b/node_modules/babel-generator/lib/generators/expressions.js
@@ -13,6 +13,7 @@ exports.ThisExpression = ThisExpression;
 exports.Super = Super;
 exports.Decorator = Decorator;
 exports.CallExpression = CallExpression;
+exports.Import = Import;
 exports.EmptyStatement = EmptyStatement;
 exports.ExpressionStatement = ExpressionStatement;
 exports.AssignmentPattern = AssignmentPattern;
@@ -21,10 +22,6 @@ exports.BindExpression = BindExpression;
 exports.MemberExpression = MemberExpression;
 exports.MetaProperty = MetaProperty;
 
-var _isNumber = require("lodash/isNumber");
-
-var _isNumber2 = _interopRequireDefault(_isNumber);
-
 var _babelTypes = require("babel-types");
 
 var t = _interopRequireWildcard(_babelTypes);
@@ -35,8 +32,6 @@ var n = _interopRequireWildcard(_node);
 
 function _interopRequireWildcard(obj) { if (obj && obj.__esModule) { return obj; } else { var newObj = {}; if (obj != null) { for (var key in obj) { if (Object.prototype.hasOwnProperty.call(obj, key)) newObj[key] = obj[key]; } } newObj.default = obj; return newObj; } }
 
-function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
-
 function UnaryExpression(node) {
   if (node.operator === "void" || node.operator === "delete" || node.operator === "typeof") {
     this.word(node.operator);
@@ -142,6 +137,10 @@ function CallExpression(node) {
   this.token(")");
 }
 
+function Import() {
+  this.word("import");
+}
+
 function buildYieldAwait(keyword) {
   return function (node) {
     this.word(keyword);
@@ -173,6 +172,8 @@ function ExpressionStatement(node) {
 
 function AssignmentPattern(node) {
   this.print(node.left, node);
+  if (node.left.optional) this.token("?");
+  this.print(node.left.typeAnnotation, node);
   this.space();
   this.token("=");
   this.space();
@@ -219,7 +220,7 @@ function MemberExpression(node) {
   }
 
   var computed = node.computed;
-  if (t.isLiteral(node.property) && (0, _isNumber2.default)(node.property.value)) {
+  if (t.isLiteral(node.property) && typeof node.property.value === "number") {
     computed = true;
   }
 
diff --git a/node_modules/babel-generator/lib/generators/flow.js b/node_modules/babel-generator/lib/generators/flow.js
index cc52ffe83..077f75cf8 100644
--- a/node_modules/babel-generator/lib/generators/flow.js
+++ b/node_modules/babel-generator/lib/generators/flow.js
@@ -321,11 +321,19 @@ function ObjectTypeAnnotation(node) {
     this.space();
 
     this.printJoin(props, node, {
+      addNewlines: function addNewlines(leading) {
+        if (leading && !props[0]) return 1;
+      },
+
       indent: true,
       statement: true,
       iterator: function iterator() {
         if (props.length !== 1) {
-          _this.semicolon();
+          if (_this.format.flowCommaSeparator) {
+            _this.token(",");
+          } else {
+            _this.semicolon();
+          }
           _this.space();
         }
       }
diff --git a/node_modules/babel-generator/lib/generators/jsx.js b/node_modules/babel-generator/lib/generators/jsx.js
index 492452899..6632db1c2 100644
--- a/node_modules/babel-generator/lib/generators/jsx.js
+++ b/node_modules/babel-generator/lib/generators/jsx.js
@@ -12,6 +12,7 @@ exports.JSXNamespacedName = JSXNamespacedName;
 exports.JSXMemberExpression = JSXMemberExpression;
 exports.JSXSpreadAttribute = JSXSpreadAttribute;
 exports.JSXExpressionContainer = JSXExpressionContainer;
+exports.JSXSpreadChild = JSXSpreadChild;
 exports.JSXText = JSXText;
 exports.JSXElement = JSXElement;
 exports.JSXOpeningElement = JSXOpeningElement;
@@ -57,6 +58,13 @@ function JSXExpressionContainer(node) {
   this.token("}");
 }
 
+function JSXSpreadChild(node) {
+  this.token("{");
+  this.token("...");
+  this.print(node.expression, node);
+  this.token("}");
+}
+
 function JSXText(node) {
   this.token(node.value);
 }
diff --git a/node_modules/babel-generator/lib/generators/modules.js b/node_modules/babel-generator/lib/generators/modules.js
index 3dcda7cca..608053540 100644
--- a/node_modules/babel-generator/lib/generators/modules.js
+++ b/node_modules/babel-generator/lib/generators/modules.js
@@ -19,6 +19,11 @@ var t = _interopRequireWildcard(_babelTypes);
 function _interopRequireWildcard(obj) { if (obj && obj.__esModule) { return obj; } else { var newObj = {}; if (obj != null) { for (var key in obj) { if (Object.prototype.hasOwnProperty.call(obj, key)) newObj[key] = obj[key]; } } newObj.default = obj; return newObj; } }
 
 function ImportSpecifier(node) {
+  if (node.importKind === "type" || node.importKind === "typeof") {
+    this.word(node.importKind);
+    this.space();
+  }
+
   this.print(node.imported, node);
   if (node.local && node.local.name !== node.imported.name) {
     this.space();
@@ -58,12 +63,6 @@ function ExportAllDeclaration(node) {
   this.word("export");
   this.space();
   this.token("*");
-  if (node.exported) {
-    this.space();
-    this.word("as");
-    this.space();
-    this.print(node.exported, node);
-  }
   this.space();
   this.word("from");
   this.space();
diff --git a/node_modules/babel-generator/lib/generators/statements.js b/node_modules/babel-generator/lib/generators/statements.js
index 1866fe00f..d74b19102 100644
--- a/node_modules/babel-generator/lib/generators/statements.js
+++ b/node_modules/babel-generator/lib/generators/statements.js
@@ -115,13 +115,12 @@ var buildForXStatement = function buildForXStatement(op) {
     if (op === "await") {
       this.word("await");
       this.space();
-      op = "of";
     }
     this.token("(");
 
     this.print(node.left, node);
     this.space();
-    this.word(op);
+    this.word(op === "await" ? "of" : op);
     this.space();
     this.print(node.right, node);
     this.token(")");
diff --git a/node_modules/babel-generator/lib/generators/template-literals.js b/node_modules/babel-generator/lib/generators/template-literals.js
index c1cdabbe0..32467eb42 100644
--- a/node_modules/babel-generator/lib/generators/template-literals.js
+++ b/node_modules/babel-generator/lib/generators/template-literals.js
@@ -15,9 +15,7 @@ function TemplateElement(node, parent) {
 
   var value = (isFirst ? "`" : "}") + node.value.raw + (isLast ? "`" : "${");
 
-  if (!isFirst) this.space();
   this.token(value);
-  if (!isLast) this.space();
 }
 
 function TemplateLiteral(node) {
diff --git a/node_modules/babel-generator/lib/generators/types.js b/node_modules/babel-generator/lib/generators/types.js
index 4dfa83735..d5e081fd2 100644
--- a/node_modules/babel-generator/lib/generators/types.js
+++ b/node_modules/babel-generator/lib/generators/types.js
@@ -128,21 +128,31 @@ function NullLiteral() {
 
 function NumericLiteral(node) {
   var raw = this.getPossibleRaw(node);
-
-  this.number(raw == null ? node.value + "" : raw);
+  var value = node.value + "";
+  if (raw == null) {
+    this.number(value);
+  } else if (this.format.minified) {
+    this.number(raw.length < value.length ? raw : value);
+  } else {
+    this.number(raw);
+  }
 }
 
 function StringLiteral(node, parent) {
   var raw = this.getPossibleRaw(node);
-  if (raw != null) {
+  if (!this.format.minified && raw != null) {
     this.token(raw);
     return;
   }
 
-  var val = (0, _jsesc2.default)(node.value, {
+  var opts = {
     quotes: t.isJSX(parent) ? "double" : this.format.quotes,
     wrap: true
-  });
+  };
+  if (this.format.jsonCompatibleStrings) {
+    opts.json = true;
+  }
+  var val = (0, _jsesc2.default)(node.value, opts);
 
   return this.token(val);
 }
\ No newline at end of file
diff --git a/node_modules/babel-generator/lib/index.js b/node_modules/babel-generator/lib/index.js
index 6c7037c35..e8da09ebf 100644
--- a/node_modules/babel-generator/lib/index.js
+++ b/node_modules/babel-generator/lib/index.js
@@ -43,11 +43,11 @@ function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { de
 var Generator = function (_Printer) {
   (0, _inherits3.default)(Generator, _Printer);
 
-  function Generator(ast, opts, code) {
+  function Generator(ast) {
+    var opts = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};
+    var code = arguments[2];
     (0, _classCallCheck3.default)(this, Generator);
 
-    opts = opts || {};
-
     var tokens = ast.tokens || [];
     var format = normalizeOptions(code, opts, tokens);
     var map = opts.sourceMaps ? new _sourceMap2.default(opts, code) : null;
@@ -83,11 +83,13 @@ function normalizeOptions(code, opts, tokens) {
     minified: opts.minified,
     concise: opts.concise,
     quotes: opts.quotes || findCommonStringDelimiter(code, tokens),
+    jsonCompatibleStrings: opts.jsonCompatibleStrings,
     indent: {
       adjustMultilineComment: true,
       style: style,
       base: 0
-    }
+    },
+    flowCommaSeparator: opts.flowCommaSeparator
   };
 
   if (format.minified) {
@@ -103,10 +105,10 @@ function normalizeOptions(code, opts, tokens) {
   }
 
   if (format.compact === "auto") {
-    format.compact = code.length > 100000;
+    format.compact = code.length > 500000;
 
     if (format.compact) {
-      console.error("[BABEL] " + messages.get("codeGeneratorDeopt", opts.filename, "100KB"));
+      console.error("[BABEL] " + messages.get("codeGeneratorDeopt", opts.filename, "500KB"));
     }
   }
 
@@ -123,7 +125,7 @@ function findCommonStringDelimiter(code, tokens) {
     return DEFAULT_STRING_DELIMITER;
   }
 
-  var occurences = {
+  var occurrences = {
     single: 0,
     double: 0
   };
@@ -136,15 +138,15 @@ function findCommonStringDelimiter(code, tokens) {
 
     var raw = code.slice(token.start, token.end);
     if (raw[0] === "'") {
-      occurences.single++;
+      occurrences.single++;
     } else {
-      occurences.double++;
+      occurrences.double++;
     }
 
     checked++;
     if (checked >= 3) break;
   }
-  if (occurences.single > occurences.double) {
+  if (occurrences.single > occurrences.double) {
     return "single";
   } else {
     return "double";
diff --git a/node_modules/babel-generator/lib/node/parentheses.js b/node_modules/babel-generator/lib/node/parentheses.js
index 10eba8e2c..471af71cb 100644
--- a/node_modules/babel-generator/lib/node/parentheses.js
+++ b/node_modules/babel-generator/lib/node/parentheses.js
@@ -5,6 +5,7 @@ exports.AwaitExpression = exports.FunctionTypeAnnotation = undefined;
 exports.NullableTypeAnnotation = NullableTypeAnnotation;
 exports.UpdateExpression = UpdateExpression;
 exports.ObjectExpression = ObjectExpression;
+exports.DoExpression = DoExpression;
 exports.Binary = Binary;
 exports.BinaryExpression = BinaryExpression;
 exports.SequenceExpression = SequenceExpression;
@@ -55,27 +56,19 @@ function NullableTypeAnnotation(node, parent) {
 
 exports.FunctionTypeAnnotation = NullableTypeAnnotation;
 function UpdateExpression(node, parent) {
-  if (t.isMemberExpression(parent) && parent.object === node) {
-    return true;
-  }
-
-  return false;
+  return t.isMemberExpression(parent) && parent.object === node;
 }
 
 function ObjectExpression(node, parent, printStack) {
   return isFirstInStatement(printStack, { considerArrow: true });
 }
 
-function Binary(node, parent) {
-  if ((t.isCallExpression(parent) || t.isNewExpression(parent)) && parent.callee === node) {
-    return true;
-  }
-
-  if (t.isUnaryLike(parent)) {
-    return true;
-  }
+function DoExpression(node, parent, printStack) {
+  return isFirstInStatement(printStack);
+}
 
-  if (t.isMemberExpression(parent) && parent.object === node) {
+function Binary(node, parent) {
+  if ((t.isCallExpression(parent) || t.isNewExpression(parent)) && parent.callee === node || t.isUnaryLike(parent) || t.isMemberExpression(parent) && parent.object === node || t.isAwaitExpression(parent)) {
     return true;
   }
 
@@ -86,11 +79,7 @@ function Binary(node, parent) {
     var nodeOp = node.operator;
     var nodePos = PRECEDENCE[nodeOp];
 
-    if (parentPos > nodePos) {
-      return true;
-    }
-
-    if (parentPos === nodePos && parent.right === node && !t.isLogicalExpression(parent)) {
+    if (parentPos === nodePos && parent.right === node && !t.isLogicalExpression(parent) || parentPos > nodePos) {
       return true;
     }
   }
@@ -99,49 +88,12 @@ function Binary(node, parent) {
 }
 
 function BinaryExpression(node, parent) {
-  if (node.operator === "in") {
-    if (t.isVariableDeclarator(parent)) {
-      return true;
-    }
-
-    if (t.isFor(parent)) {
-      return true;
-    }
-  }
-
-  return false;
+  return node.operator === "in" && (t.isVariableDeclarator(parent) || t.isFor(parent));
 }
 
 function SequenceExpression(node, parent) {
-  if (t.isForStatement(parent)) {
-    return false;
-  }
-
-  if (t.isExpressionStatement(parent) && parent.expression === node) {
-    return false;
-  }
-
-  if (t.isReturnStatement(parent)) {
-    return false;
-  }
-
-  if (t.isThrowStatement(parent)) {
-    return false;
-  }
-
-  if (t.isSwitchStatement(parent) && parent.discriminant === node) {
-    return false;
-  }
-
-  if (t.isWhileStatement(parent) && parent.test === node) {
-    return false;
-  }
 
-  if (t.isIfStatement(parent) && parent.test === node) {
-    return false;
-  }
-
-  if (t.isForInStatement(parent) && parent.right === node) {
+  if (t.isForStatement(parent) || t.isThrowStatement(parent) || t.isReturnStatement(parent) || t.isIfStatement(parent) && parent.test === node || t.isWhileStatement(parent) && parent.test === node || t.isForInStatement(parent) && parent.right === node || t.isSwitchStatement(parent) && parent.discriminant === node || t.isExpressionStatement(parent) && parent.expression === node) {
     return false;
   }
 
@@ -158,15 +110,7 @@ function ClassExpression(node, parent, printStack) {
 }
 
 function UnaryLike(node, parent) {
-  if (t.isMemberExpression(parent, { object: node })) {
-    return true;
-  }
-
-  if (t.isCallExpression(parent, { callee: node }) || t.isNewExpression(parent, { callee: node })) {
-    return true;
-  }
-
-  return false;
+  return t.isMemberExpression(parent, { object: node }) || t.isCallExpression(parent, { callee: node }) || t.isNewExpression(parent, { callee: node });
 }
 
 function FunctionExpression(node, parent, printStack) {
@@ -174,15 +118,7 @@ function FunctionExpression(node, parent, printStack) {
 }
 
 function ArrowFunctionExpression(node, parent) {
-  if (t.isExportDeclaration(parent)) {
-    return true;
-  }
-
-  if (t.isBinaryExpression(parent) || t.isLogicalExpression(parent)) {
-    return true;
-  }
-
-  if (t.isUnaryExpression(parent)) {
+  if (t.isExportDeclaration(parent) || t.isBinaryExpression(parent) || t.isLogicalExpression(parent) || t.isUnaryExpression(parent) || t.isTaggedTemplateExpression(parent)) {
     return true;
   }
 
@@ -190,15 +126,7 @@ function ArrowFunctionExpression(node, parent) {
 }
 
 function ConditionalExpression(node, parent) {
-  if (t.isUnaryLike(parent)) {
-    return true;
-  }
-
-  if (t.isBinary(parent)) {
-    return true;
-  }
-
-  if (t.isConditionalExpression(parent, { test: node })) {
+  if (t.isUnaryLike(parent) || t.isBinary(parent) || t.isConditionalExpression(parent, { test: node }) || t.isAwaitExpression(parent)) {
     return true;
   }
 
@@ -214,27 +142,18 @@ function AssignmentExpression(node) {
 }
 
 function isFirstInStatement(printStack) {
-  var _ref = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};
-
-  var _ref$considerArrow = _ref.considerArrow;
-  var considerArrow = _ref$considerArrow === undefined ? false : _ref$considerArrow;
-  var _ref$considerDefaultE = _ref.considerDefaultExports;
-  var considerDefaultExports = _ref$considerDefaultE === undefined ? false : _ref$considerDefaultE;
+  var _ref = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {},
+      _ref$considerArrow = _ref.considerArrow,
+      considerArrow = _ref$considerArrow === undefined ? false : _ref$considerArrow,
+      _ref$considerDefaultE = _ref.considerDefaultExports,
+      considerDefaultExports = _ref$considerDefaultE === undefined ? false : _ref$considerDefaultE;
 
   var i = printStack.length - 1;
   var node = printStack[i];
   i--;
   var parent = printStack[i];
   while (i > 0) {
-    if (t.isExpressionStatement(parent, { expression: node })) {
-      return true;
-    }
-
-    if (considerDefaultExports && t.isExportDefaultDeclaration(parent, { declaration: node })) {
-      return true;
-    }
-
-    if (considerArrow && t.isArrowFunctionExpression(parent, { body: node })) {
+    if (t.isExpressionStatement(parent, { expression: node }) || t.isTaggedTemplateExpression(parent) || considerDefaultExports && t.isExportDefaultDeclaration(parent, { declaration: node }) || considerArrow && t.isArrowFunctionExpression(parent, { body: node })) {
       return true;
     }
 
diff --git a/node_modules/babel-generator/lib/node/whitespace.js b/node_modules/babel-generator/lib/node/whitespace.js
index d3690a84a..f39e75525 100644
--- a/node_modules/babel-generator/lib/node/whitespace.js
+++ b/node_modules/babel-generator/lib/node/whitespace.js
@@ -1,13 +1,5 @@
 "use strict";
 
-var _isBoolean = require("lodash/isBoolean");
-
-var _isBoolean2 = _interopRequireDefault(_isBoolean);
-
-var _each = require("lodash/each");
-
-var _each2 = _interopRequireDefault(_each);
-
 var _map = require("lodash/map");
 
 var _map2 = _interopRequireDefault(_map);
@@ -144,19 +136,14 @@ exports.list = {
   }
 };
 
-(0, _each2.default)({
-  Function: true,
-  Class: true,
-  Loop: true,
-  LabeledStatement: true,
-  SwitchStatement: true,
-  TryStatement: true
-}, function (amounts, type) {
-  if ((0, _isBoolean2.default)(amounts)) {
+[["Function", true], ["Class", true], ["Loop", true], ["LabeledStatement", true], ["SwitchStatement", true], ["TryStatement", true]].forEach(function (_ref) {
+  var type = _ref[0],
+      amounts = _ref[1];
+
+  if (typeof amounts === "boolean") {
     amounts = { after: amounts, before: amounts };
   }
-
-  (0, _each2.default)([type].concat(t.FLIPPED_ALIAS_KEYS[type] || []), function (type) {
+  [type].concat(t.FLIPPED_ALIAS_KEYS[type] || []).forEach(function (type) {
     exports.nodes[type] = function () {
       return amounts;
     };
diff --git a/node_modules/babel-generator/lib/printer.js b/node_modules/babel-generator/lib/printer.js
index 058ad72b7..8eb3eddac 100644
--- a/node_modules/babel-generator/lib/printer.js
+++ b/node_modules/babel-generator/lib/printer.js
@@ -340,8 +340,6 @@ var Printer = function () {
   };
 
   Printer.prototype.getPossibleRaw = function getPossibleRaw(node) {
-    if (this.format.minified) return;
-
     var extra = node.extra;
     if (extra && extra.raw != null && extra.rawValue != null && node.value === extra.rawValue) {
       return extra.raw;
diff --git a/node_modules/babel-generator/lib/source-map.js b/node_modules/babel-generator/lib/source-map.js
index 192d8bca0..b44d1f080 100644
--- a/node_modules/babel-generator/lib/source-map.js
+++ b/node_modules/babel-generator/lib/source-map.js
@@ -22,27 +22,38 @@ function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { de
 
 var SourceMap = function () {
   function SourceMap(opts, code) {
-    var _this = this;
-
     (0, _classCallCheck3.default)(this, SourceMap);
 
+    this._cachedMap = null;
+    this._code = code;
     this._opts = opts;
-    this._map = new _sourceMap2.default.SourceMapGenerator({
-      file: opts.sourceMapTarget,
-      sourceRoot: opts.sourceRoot
-    });
+    this._rawMappings = [];
+  }
 
-    if (typeof code === "string") {
-      this._map.setSourceContent(opts.sourceFileName, code);
-    } else if ((typeof code === "undefined" ? "undefined" : (0, _typeof3.default)(code)) === "object") {
-      (0, _keys2.default)(code).forEach(function (sourceFileName) {
-        _this._map.setSourceContent(sourceFileName, code[sourceFileName]);
+  SourceMap.prototype.get = function get() {
+    if (!this._cachedMap) {
+      var map = this._cachedMap = new _sourceMap2.default.SourceMapGenerator({
+        file: this._opts.sourceMapTarget,
+        sourceRoot: this._opts.sourceRoot
       });
+
+      var code = this._code;
+      if (typeof code === "string") {
+        map.setSourceContent(this._opts.sourceFileName, code);
+      } else if ((typeof code === "undefined" ? "undefined" : (0, _typeof3.default)(code)) === "object") {
+        (0, _keys2.default)(code).forEach(function (sourceFileName) {
+          map.setSourceContent(sourceFileName, code[sourceFileName]);
+        });
+      }
+
+      this._rawMappings.forEach(map.addMapping, map);
     }
-  }
 
-  SourceMap.prototype.get = function get() {
-    return this._map.toJSON();
+    return this._cachedMap.toJSON();
+  };
+
+  SourceMap.prototype.getRawMappings = function getRawMappings() {
+    return this._rawMappings.slice();
   };
 
   SourceMap.prototype.mark = function mark(generatedLine, generatedColumn, line, column, identifierName, filename) {
@@ -52,18 +63,19 @@ var SourceMap = function () {
       return;
     }
 
+    this._cachedMap = null;
     this._lastGenLine = generatedLine;
     this._lastSourceLine = line;
     this._lastSourceColumn = column;
 
-    this._map.addMapping({
-      name: identifierName,
+    this._rawMappings.push({
+      name: identifierName || undefined,
       generated: {
         line: generatedLine,
         column: generatedColumn
       },
-      source: line == null ? null : filename || this._opts.sourceFileName,
-      original: line == null ? null : {
+      source: line == null ? undefined : filename || this._opts.sourceFileName,
+      original: line == null ? undefined : {
         line: line,
         column: column
       }