regenerator spring cleaning

lib/6to5/transformation/transformers/generators/emit.js

@@ -8,57 +8,50 @@
  * the same directory.
  */
 
-var assert = require("assert");
-var types = require("ast-types");
-var b = types.builders;
-var n = types.namedTypes;
-var leap = require("./leap");
-var meta = require("./meta");
+exports.Emitter = Emitter;
+
 var runtimeProperty = require("./util").runtimeProperty;
+var assert          = require("assert");
+var types           = require("ast-types");
+var leap            = require("./leap");
+var meta            = require("./meta");
+var _               = require("lodash");
+
 var runtimeKeysMethod = runtimeProperty("keys");
-var hasOwn = Object.prototype.hasOwnProperty;
+var b                 = types.builders;
+var n                 = types.namedTypes;
 
 function Emitter(contextId) {
   assert.ok(this instanceof Emitter);
   n.Identifier.assert(contextId);
 
-  Object.defineProperties(this, {
-    // In order to make sure the context object does not collide with
-    // anything in the local scope, we might have to rename it, so we
-    // refer to it symbolically instead of just assuming that it will be
-    // called "context".
-    contextId: { value: contextId },
+  // In order to make sure the context object does not collide with
+  // anything in the local scope, we might have to rename it, so we
+  // refer to it symbolically instead of just assuming that it will be
+  // called "context".
+  this.contextId = contextId;
 
-    // An append-only list of Statements that grows each time this.emit is
-    // called.
-    listing: { value: [] },
+  // An append-only list of Statements that grows each time this.emit is
+  // called.
+  this.listing = [];
 
-    // A sparse array whose keys correspond to locations in this.listing
-    // that have been marked as branch/jump targets.
-    marked: { value: [true] },
+  // A sparse array whose keys correspond to locations in this.listing
+  // that have been marked as branch/jump targets.
+  this.marked = [true];
 
-    // The last location will be marked when this.getDispatchLoop is
-    // called.
-    finalLoc: { value: loc() },
+  // The last location will be marked when this.getDispatchLoop is
+  // called.
+  this.finalLoc = loc();
 
-    // A list of all leap.TryEntry statements emitted.
-    tryEntries: { value: [] }
-  });
+  // A list of all leap.TryEntry statements emitted.
+  this.tryEntries = [];
 
-  // The .leapManager property needs to be defined by a separate
-  // defineProperties call so that .finalLoc will be visible to the
-  // leap.LeapManager constructor.
-  Object.defineProperties(this, {
-    // Each time we evaluate the body of a loop, we tell this.leapManager
-    // to enter a nested loop context that determines the meaning of break
-    // and continue statements therein.
-    leapManager: { value: new leap.LeapManager(this) }
-  });
+  // Each time we evaluate the body of a loop, we tell this.leapManager
+  // to enter a nested loop context that determines the meaning of break
+  // and continue statements therein.
+  this.leapManager = new leap.LeapManager(this);
 }
 
-var Ep = Emitter.prototype;
-exports.Emitter = Emitter;
-
 // Offsets into this.listing that could be used as targets for branches or
 // jumps are represented as numeric Literal nodes. This representation has
 // the amazingly convenient benefit of allowing the exact value of the
@@ -70,7 +63,7 @@ function loc() {
 
 // Sets the exact value of the given location to the offset of the next
 // Statement emitted.
-Ep.mark = function(loc) {
+Emitter.prototype.mark = function(loc) {
   n.Literal.assert(loc);
   var index = this.listing.length;
   if (loc.value === -1) {
@@ -84,29 +77,28 @@ Ep.mark = function(loc) {
   return loc;
 };
 
-Ep.emit = function(node) {
-  if (n.Expression.check(node))
-    node = b.expressionStatement(node);
+Emitter.prototype.emit = function(node) {
+  if (n.Expression.check(node)) node = b.expressionStatement(node);
   n.Statement.assert(node);
   this.listing.push(node);
 };
 
 // Shorthand for emitting assignment statements. This will come in handy
 // for assignments to temporary variables.
-Ep.emitAssign = function(lhs, rhs) {
+Emitter.prototype.emitAssign = function(lhs, rhs) {
   this.emit(this.assign(lhs, rhs));
   return lhs;
 };
 
 // Shorthand for an assignment statement.
-Ep.assign = function(lhs, rhs) {
+Emitter.prototype.assign = function(lhs, rhs) {
   return b.expressionStatement(
     b.assignmentExpression("=", lhs, rhs));
 };
 
 // Convenience function for generating expressions like context.next,
 // context.sent, and context.rval.
-Ep.contextProperty = function(name, computed) {
+Emitter.prototype.contextProperty = function(name, computed) {
   return b.memberExpression(
     this.contextId,
     computed ? b.literal(name) : b.identifier(name),
@@ -124,7 +116,7 @@ var volatileContextPropertyNames = {
 // A "volatile" context property is a MemberExpression like context.sent
 // that should probably be stored in a temporary variable when there's a
 // possibility the property will get overwritten.
-Ep.isVolatileContextProperty = function(expr) {
+Emitter.prototype.isVolatileContextProperty = function(expr) {
   if (n.MemberExpression.check(expr)) {
     if (expr.computed) {
       // If it's a computed property such as context[couldBeAnything],
@@ -135,8 +127,7 @@ Ep.isVolatileContextProperty = function(expr) {
     if (n.Identifier.check(expr.object) &&
         n.Identifier.check(expr.property) &&
         expr.object.name === this.contextId.name &&
-        hasOwn.call(volatileContextPropertyNames,
-                    expr.property.name)) {
+        _.has(volatileContextPropertyNames, expr.property.name)) {
       return true;
     }
   }
@@ -145,7 +136,7 @@ Ep.isVolatileContextProperty = function(expr) {
 };
 
 // Shorthand for setting context.rval and jumping to `context.stop()`.
-Ep.stop = function(rval) {
+Emitter.prototype.stop = function(rval) {
   if (rval) {
     this.setReturnValue(rval);
   }
@@ -153,7 +144,7 @@ Ep.stop = function(rval) {
   this.jump(this.finalLoc);
 };
 
-Ep.setReturnValue = function(valuePath) {
+Emitter.prototype.setReturnValue = function(valuePath) {
   n.Expression.assert(valuePath.value);
 
   this.emitAssign(
@@ -162,7 +153,7 @@ Ep.setReturnValue = function(valuePath) {
   );
 };
 
-Ep.clearPendingException = function(tryLoc, assignee) {
+Emitter.prototype.clearPendingException = function(tryLoc, assignee) {
   n.Literal.assert(tryLoc);
 
   var catchCall = b.callExpression(
@@ -179,13 +170,13 @@ Ep.clearPendingException = function(tryLoc, assignee) {
 
 // Emits code for an unconditional jump to the given location, even if the
 // exact value of the location is not yet known.
-Ep.jump = function(toLoc) {
+Emitter.prototype.jump = function(toLoc) {
   this.emitAssign(this.contextProperty("next"), toLoc);
   this.emit(b.breakStatement());
 };
 
 // Conditional jump.
-Ep.jumpIf = function(test, toLoc) {
+Emitter.prototype.jumpIf = function(test, toLoc) {
   n.Expression.assert(test);
   n.Literal.assert(toLoc);
 
@@ -199,13 +190,12 @@ Ep.jumpIf = function(test, toLoc) {
 };
 
 // Conditional jump, with the condition negated.
-Ep.jumpIfNot = function(test, toLoc) {
+Emitter.prototype.jumpIfNot = function(test, toLoc) {
   n.Expression.assert(test);
   n.Literal.assert(toLoc);
 
   var negatedTest;
-  if (n.UnaryExpression.check(test) &&
-      test.operator === "!") {
+  if (n.UnaryExpression.check(test) && test.operator === "!") {
     // Avoid double negation.
     negatedTest = test.argument;
   } else {
@@ -227,13 +217,13 @@ Ep.jumpIfNot = function(test, toLoc) {
 // other local variables, and since we just increment `nextTempId`
 // monotonically, uniqueness is assured.
 var nextTempId = 0;
-Ep.makeTempVar = function() {
+Emitter.prototype.makeTempVar = function() {
   return this.contextProperty("t" + nextTempId++);
 };
 
-Ep.getContextFunction = function(id) {
+Emitter.prototype.getContextFunction = function(id) {
   var node = b.functionExpression(
-    id || null/*Anonymous*/,
+    id || null,
     [this.contextId],
     b.blockStatement([this.getDispatchLoop()]),
     false, // Not a generator anymore!
@@ -254,7 +244,7 @@ Ep.getContextFunction = function(id) {
 //
 // Each marked location in this.listing will correspond to one generated
 // case statement.
-Ep.getDispatchLoop = function() {
+Emitter.prototype.getDispatchLoop = function() {
   var self = this;
   var cases = [];
   var current;
@@ -265,9 +255,7 @@ Ep.getDispatchLoop = function() {
 
   self.listing.forEach(function(stmt, i) {
     if (self.marked.hasOwnProperty(i)) {
-      cases.push(b.switchCase(
-        b.literal(i),
-        current = []));
+      cases.push(b.switchCase(b.literal(i), current = []));
       alreadyEnded = false;
     }
 
@@ -318,7 +306,7 @@ function isSwitchCaseEnder(stmt) {
          n.ThrowStatement.check(stmt);
 }
 
-Ep.getTryEntryList = function() {
+Emitter.prototype.getTryEntryList = function() {
   if (this.tryEntries.length === 0) {
     // To avoid adding a needless [] to the majority of runtime.wrap
     // argument lists, force the caller to handle this case specially.
@@ -358,7 +346,7 @@ Ep.getTryEntryList = function() {
 
 // No destructive modification of AST nodes.
 
-Ep.explode = function(path, ignoreResult) {
+Emitter.prototype.explode = function(path, ignoreResult) {
   assert.ok(path instanceof types.NodePath);
 
   var node = path.value;
@@ -377,10 +365,7 @@ Ep.explode = function(path, ignoreResult) {
 
   switch (node.type) {
   case "Program":
-    return path.get("body").map(
-      self.explodeStatement,
-      self
-    );
+    return path.get("body").map(self.explodeStatement, self);
 
   case "VariableDeclarator":
     throw getDeclError(node);
@@ -390,13 +375,10 @@ Ep.explode = function(path, ignoreResult) {
   case "Property":
   case "SwitchCase":
   case "CatchClause":
-    throw new Error(
-      node.type + " nodes should be handled by their parents");
+    throw new Error(node.type + " nodes should be handled by their parents");
 
   default:
-    throw new Error(
-      "unknown Node of type " +
-        JSON.stringify(node.type));
+    throw new Error("unknown Node of type " + JSON.stringify(node.type));
   }
 };
 
@@ -407,7 +389,7 @@ function getDeclError(node) {
     JSON.stringify(node));
 }
 
-Ep.explodeStatement = function(path, labelId) {
+Emitter.prototype.explodeStatement = function(path, labelId) {
   assert.ok(path instanceof types.NodePath);
 
   var stmt = path.value;
@@ -768,18 +750,15 @@ Ep.explodeStatement = function(path, labelId) {
     break;
 
   default:
-    throw new Error(
-      "unknown Statement of type " +
-        JSON.stringify(stmt.type));
+    throw new Error("unknown Statement of type " + JSON.stringify(stmt.type));
   }
 };
 
-Ep.emitAbruptCompletion = function(record) {
+Emitter.prototype.emitAbruptCompletion = function(record) {
   if (!isValidCompletion(record)) {
     assert.ok(
       false,
-      "invalid completion record: " +
-        JSON.stringify(record)
+      "invalid completion record: " + JSON.stringify(record)
     );
   }
 
@@ -790,12 +769,10 @@ Ep.emitAbruptCompletion = function(record) {
 
   var abruptArgs = [b.literal(record.type)];
 
-  if (record.type === "break" ||
-      record.type === "continue") {
+  if (record.type === "break" || record.type === "continue") {
     n.Literal.assert(record.target);
     abruptArgs[1] = record.target;
-  } else if (record.type === "return" ||
-             record.type === "throw") {
+  } else if (record.type === "return" || record.type === "throw") {
     if (record.value) {
       n.Expression.assert(record.value);
       abruptArgs[1] = record.value;
@@ -816,15 +793,15 @@ function isValidCompletion(record) {
   var type = record.type;
 
   if (type === "normal") {
-    return !hasOwn.call(record, "target");
+    return !_.has(record, "target");
   }
 
   if (type === "break" || type === "continue") {
-    return !hasOwn.call(record, "value") && n.Literal.check(record.target);
+    return !_.has(record, "value") && n.Literal.check(record.target);
   }
 
   if (type === "return" || type === "throw") {
-    return hasOwn.call(record, "value") && !hasOwn.call(record, "target");
+    return _.has(record, "value") && !_.has(record, "target");
   }
 
   return false;
@@ -840,7 +817,7 @@ function isValidCompletion(record) {
 // statements). There's no logical harm in marking such locations as jump
 // targets, but minimizing the number of switch cases keeps the generated
 // code shorter.
-Ep.getUnmarkedCurrentLoc = function() {
+Emitter.prototype.getUnmarkedCurrentLoc = function() {
   return b.literal(this.listing.length);
 };
 
@@ -854,7 +831,7 @@ Ep.getUnmarkedCurrentLoc = function() {
 // would know the location of the current instruction with complete
 // precision at all times, but we don't have that luxury here, as it would
 // be costly and verbose to set context.prev before every statement.
-Ep.updateContextPrevLoc = function(loc) {
+Emitter.prototype.updateContextPrevLoc = function(loc) {
   if (loc) {
     n.Literal.assert(loc);
 
@@ -877,7 +854,7 @@ Ep.updateContextPrevLoc = function(loc) {
   this.emitAssign(this.contextProperty("prev"), loc);
 };
 
-Ep.explodeExpression = function(path, ignoreResult) {
+Emitter.prototype.explodeExpression = function(path, ignoreResult) {
   assert.ok(path instanceof types.NodePath);
 
   var expr = path.value;

lib/6to5/transformation/transformers/generators/hoist.js

@@ -9,10 +9,11 @@
  */
 
 var assert = require("assert");
-var types = require("ast-types");
+var types  = require("ast-types");
+var _      = require("lodash");
+
 var n = types.namedTypes;
 var b = types.builders;
-var hasOwn = Object.prototype.hasOwnProperty;
 
 // The hoist function takes a FunctionExpression or FunctionDeclaration
 // and replaces any Declaration nodes in its body with assignments, then
@@ -139,7 +140,7 @@ exports.hoist = function(funPath) {
   var declarations = [];
 
   Object.keys(vars).forEach(function(name) {
-    if (!hasOwn.call(paramNames, name)) {
+    if (!_.has(paramNames, name)) {
       declarations.push(b.variableDeclarator(vars[name], null));
     }
   });

lib/6to5/transformation/transformers/generators/leap.js

@@ -8,10 +8,20 @@
  * the same directory.
  */
 
+exports.FunctionEntry = FunctionEntry;
+exports.FinallyEntry  = FinallyEntry;
+exports.SwitchEntry   = SwitchEntry;
+exports.LeapManager   = LeapManager;
+exports.CatchEntry    = CatchEntry;
+exports.LoopEntry     = LoopEntry;
+exports.TryEntry      = TryEntry;
+
 var assert = require("assert");
-var types = require("ast-types");
-var n = types.namedTypes;
-var inherits = require("util").inherits;
+var types  = require("ast-types");
+var util   = require("util");
+
+var inherits = util.inherits;
+var n        = types.namedTypes;
 
 function Entry() {
   assert.ok(this instanceof Entry);
@@ -22,13 +32,10 @@ function FunctionEntry(returnLoc) {
 
   n.Literal.assert(returnLoc);
 
-  Object.defineProperties(this, {
-    returnLoc: { value: returnLoc }
-  });
+  this.returnLoc = returnLoc;
 }
 
 inherits(FunctionEntry, Entry);
-exports.FunctionEntry = FunctionEntry;
 
 function LoopEntry(breakLoc, continueLoc, label) {
   Entry.call(this);
@@ -42,28 +49,22 @@ function LoopEntry(breakLoc, continueLoc, label) {
     label = null;
   }
 
-  Object.defineProperties(this, {
-    breakLoc: { value: breakLoc },
-    continueLoc: { value: continueLoc },
-    label: { value: label }
-  });
+  this.breakLoc = breakLoc;
+  this.continueLoc = continueLoc;
+  this.label = label;
 }
 
 inherits(LoopEntry, Entry);
-exports.LoopEntry = LoopEntry;
 
 function SwitchEntry(breakLoc) {
   Entry.call(this);
 
   n.Literal.assert(breakLoc);
 
-  Object.defineProperties(this, {
-    breakLoc: { value: breakLoc }
-  });
+  this.breakLoc = breakLoc;
 }
 
 inherits(SwitchEntry, Entry);
-exports.SwitchEntry = SwitchEntry;
 
 function TryEntry(firstLoc, catchEntry, finallyEntry) {
   Entry.call(this);
@@ -85,15 +86,12 @@ function TryEntry(firstLoc, catchEntry, finallyEntry) {
   // Have to have one or the other (or both).
   assert.ok(catchEntry || finallyEntry);
 
-  Object.defineProperties(this, {
-    firstLoc: { value: firstLoc },
-    catchEntry: { value: catchEntry },
-    finallyEntry: { value: finallyEntry }
-  });
+  this.firstLoc = firstLoc;
+  this.catchEntry = catchEntry;
+  this.finallyEntry = finallyEntry;
 }
 
 inherits(TryEntry, Entry);
-exports.TryEntry = TryEntry;
 
 function CatchEntry(firstLoc, paramId) {
   Entry.call(this);
@@ -101,27 +99,21 @@ function CatchEntry(firstLoc, paramId) {
   n.Literal.assert(firstLoc);
   n.Identifier.assert(paramId);
 
-  Object.defineProperties(this, {
-    firstLoc: { value: firstLoc },
-    paramId: { value: paramId }
-  });
+  this.firstLoc = firstLoc;
+  this.paramId = paramId;
 }
 
 inherits(CatchEntry, Entry);
-exports.CatchEntry = CatchEntry;
 
 function FinallyEntry(firstLoc) {
   Entry.call(this);
 
   n.Literal.assert(firstLoc);
 
-  Object.defineProperties(this, {
-    firstLoc: { value: firstLoc }
-  });
+  this.firstLoc = firstLoc;
 }
 
 inherits(FinallyEntry, Entry);
-exports.FinallyEntry = FinallyEntry;
 
 function LeapManager(emitter) {
   assert.ok(this instanceof LeapManager);
@@ -129,18 +121,11 @@ function LeapManager(emitter) {
   var Emitter = require("./emit").Emitter;
   assert.ok(emitter instanceof Emitter);
 
-  Object.defineProperties(this, {
-    emitter: { value: emitter },
-    entryStack: {
-      value: [new FunctionEntry(emitter.finalLoc)]
-    }
-  });
+  this.emitter = emitter;
+  this.entryStack = [new FunctionEntry(emitter.finalLoc)];
 }
 
-var LMp = LeapManager.prototype;
-exports.LeapManager = LeapManager;
-
-LMp.withEntry = function(entry, callback) {
+LeapManager.prototype.withEntry = function(entry, callback) {
   assert.ok(entry instanceof Entry);
   this.entryStack.push(entry);
   try {
@@ -151,7 +136,7 @@ LMp.withEntry = function(entry, callback) {
   }
 };
 
-LMp._findLeapLocation = function(property, label) {
+LeapManager.prototype._findLeapLocation = function(property, label) {
   for (var i = this.entryStack.length - 1; i >= 0; --i) {
     var entry = this.entryStack[i];
     var loc = entry[property];
@@ -170,10 +155,10 @@ LMp._findLeapLocation = function(property, label) {
   return null;
 };
 
-LMp.getBreakLoc = function(label) {
+LeapManager.prototype.getBreakLoc = function(label) {
   return this._findLeapLocation("breakLoc", label);
 };
 
-LMp.getContinueLoc = function(label) {
+LeapManager.prototype.getContinueLoc = function(label) {
   return this._findLeapLocation("continueLoc", label);
 };

lib/6to5/transformation/transformers/generators/meta.js

@@ -9,11 +9,12 @@
  */
 
 var assert = require("assert");
-var types = require("ast-types");
-var m = require("private").makeAccessor();
+var types  = require("ast-types");
+var m      = require("private").makeAccessor();
+var _      = require("lodash");
+
 var isArray = types.builtInTypes.array;
-var n = types.namedTypes;
-var hasOwn = Object.prototype.hasOwnProperty;
+var n       = types.namedTypes;
 
 function makePredicate(propertyName, knownTypes) {
   function onlyChildren(node) {
@@ -45,16 +46,13 @@ function makePredicate(propertyName, knownTypes) {
     n.Node.assert(node);
 
     var meta = m(node);
-    if (hasOwn.call(meta, propertyName))
-      return meta[propertyName];
+    if (_.has(meta, propertyName)) return meta[propertyName];
 
     // Certain types are "opaque," which means they have no side
     // effects or leaps and we don't care about their subexpressions.
-    if (hasOwn.call(opaqueTypes, node.type))
-      return meta[propertyName] = false;
+    if (_.has(opaqueTypes, node.type)) return meta[propertyName] = false;
 
-    if (hasOwn.call(knownTypes, node.type))
-      return meta[propertyName] = true;
+    if (_.has(knownTypes, node.type)) return meta[propertyName] = true;
 
     return meta[propertyName] = onlyChildren(node);
   }
@@ -91,7 +89,7 @@ var leapTypes = {
 
 // All leap types are also side effect types.
 for (var type in leapTypes) {
-  if (hasOwn.call(leapTypes, type)) {
+  if (_.has(leapTypes, type)) {
     sideEffectTypes[type] = leapTypes[type];
   }
 }

lib/6to5/transformation/transformers/generators/runtime.js

@@ -12,9 +12,9 @@ if (typeof global.regeneratorRuntime === "object") {
   return;
 }
 
-var hasOwn = Object.prototype.hasOwnProperty;
 var iteratorSymbol = typeof Symbol === "function" && Symbol.iterator || "@@iterator";
 var runtime = global.regeneratorRuntime = exports;
+var hasOwn = Object.prototype.hasOwnProperty;
 
 var wrap = runtime.wrap = function wrap(innerFn, outerFn, self, tryList) {
   return new Generator(innerFn, outerFn, self || null, tryList || []);
@@ -412,8 +412,7 @@ Context.prototype = {
       throw record.arg;
     }
 
-    if (record.type === "break" ||
-        record.type === "continue") {
+    if (record.type === "break" || record.type === "continue") {
       this.next = record.arg;
     } else if (record.type === "return") {
       this.rval = record.arg;

lib/6to5/transformation/transformers/generators/util.js

@@ -8,30 +8,11 @@
  * the same directory.
  */
 
-var b = require("ast-types").builders;
-var hasOwn = Object.prototype.hasOwnProperty;
+var t = require("../../../types");
 
-exports.defaults = function(obj) {
-  var len = arguments.length;
-  var extension;
-
-  for (var i = 1; i < len; ++i) {
-    if ((extension = arguments[i])) {
-      for (var key in extension) {
-        if (hasOwn.call(extension, key) && !hasOwn.call(obj, key)) {
-          obj[key] = extension[key];
-        }
-      }
-    }
-  }
-
-  return obj;
-};
-
-exports.runtimeProperty = function(name) {
-  return b.memberExpression(
-    b.identifier("regeneratorRuntime"),
-    b.identifier(name),
-    false
+exports.runtimeProperty = function (name) {
+  return t.memberExpression(
+    t.identifier("regeneratorRuntime"),
+    t.identifier(name)
   );
 };

lib/6to5/transformation/transformers/generators/visit.js

@@ -200,8 +200,7 @@ function shouldNotHoistAbove(stmtPath) {
     for (var i = 0; i < value.declarations.length; ++i) {
       var decl = value.declarations[i];
       if (n.CallExpression.check(decl.init) &&
-          types.astNodesAreEquivalent(decl.init.callee,
-                                      runtimeMarkMethod)) {
+          types.astNodesAreEquivalent(decl.init.callee, runtimeMarkMethod)) {
         return true;
       }
     }