use simple loops always in array comprehensions, support yield inside of array comprehensions - closes #325, fixes #252

lib/6to5/transformation/templates/array-expression-comprehension-filter.js

@@ -1,5 +0,0 @@
-ARRAY.filter(function (KEY) {
-  return FILTER;
-}).map(function (KEY) {
-  return STATEMENT;
-});

lib/6to5/transformation/templates/array-expression-comprehension-map.js

@@ -1,3 +0,0 @@
-ARRAY.map(function (KEY) {
-  return STATEMENT;
-});

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

@@ -1,43 +1,25 @@
-var util = require("../../util");
-var t    = require("../../types");
+var traverse = require("../../traverse");
+var util     = require("../../util");
+var t        = require("../../types");
 
 exports.experimental = true;
 
-var single = function (node, file) {
-  var block = node.blocks[0];
-
-  var templateName = "array-expression-comprehension-map";
-  if (node.filter) templateName = "array-expression-comprehension-filter";
-
-  var result = util.template(templateName, {
-    STATEMENT: node.body,
-    FILTER:    node.filter,
-    ARRAY:     file.toArray(block.right),
-    KEY:       block.left
-  });
-
-  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;
-};
-
-var multiple = function (node, file) {
+var build = function (node, file) {
   var uid = file.generateUidIdentifier("arr");
 
   var container = util.template("array-comprehension-container", {
     KEY: uid
   });
-  container.callee.expression._aliasFunction = true;
+  container.callee._aliasFunction = true;
 
   var block = container.callee.body;
   var body  = block.body;
 
+  if (traverse.hasType(node, "YieldExpression", t.FUNCTION_TYPES)) {
+    container.generator = true;
+    container = t.yieldExpression(container, true);
+  }
+
   var returnStatement = body.pop();
 
   body.push(exports._build(node, function () {
@@ -76,9 +58,5 @@ exports._build = function (node, buildBody) {
 exports.ComprehensionExpression = function (node, parent, file) {
   if (node.generator) return;
 
-  if (node.blocks.length === 1) {
-    return single(node, file);
-  } else {
-    return multiple(node, file);
-  }
+  return build(node, file);
 };

test/fixtures/transformation/es7-array-comprehension/arguments/expected.js

@@ -2,9 +2,16 @@
 
 function add() {
   var _arguments = arguments;
-  return [1, 2, 3].map(function (i) {
-    return i * _arguments[0];
-  });
+  return (function () {
+    var _arr = [];
+
+    for (var _iterator = [1, 2, 3][Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
+      var i = _step.value;
+      _arr.push(i * _arguments[0]);
+    }
+
+    return _arr;
+  })();
 }
 
 add(5);

test/fixtures/transformation/es7-array-comprehension/array-expression-single-if/expected.js

@@ -1,7 +1,14 @@
 "use strict";
 
-var arr = [1, 2, 3].filter(function (i) {
-  return i > 1;
-}).map(function (i) {
-  return i * i;
-});
+var arr = (function () {
+  var _arr = [];
+
+  for (var _iterator = [1, 2, 3][Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
+    var i = _step.value;
+    if (i > 1) {
+      _arr.push(i * i);
+    }
+  }
+
+  return _arr;
+})();

test/fixtures/transformation/es7-array-comprehension/array-expression-single/expected.js

@@ -1,5 +1,12 @@
 "use strict";
 
-var arr = [1, 2, 3].map(function (i) {
-  return i * i;
-});
+var arr = (function () {
+  var _arr = [];
+
+  for (var _iterator = [1, 2, 3][Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
+    var i = _step.value;
+    _arr.push(i * i);
+  }
+
+  return _arr;
+})();

test/fixtures/transformation/es7-array-comprehension/single-if/expected.js

@@ -1,11 +1,14 @@
 "use strict";
 
-var _toArray = function (arr) {
-  return Array.isArray(arr) ? arr : Array.from(arr);
-};
+var arr = (function () {
+  var _arr = [];
 
-var arr = _toArray(nums).filter(function (i) {
-  return i > 1;
-}).map(function (i) {
-  return i * i;
-});
+  for (var _iterator = nums[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
+    var i = _step.value;
+    if (i > 1) {
+      _arr.push(i * i);
+    }
+  }
+
+  return _arr;
+})();

test/fixtures/transformation/es7-array-comprehension/single/expected.js

@@ -1,9 +1,12 @@
 "use strict";
 
-var _toArray = function (arr) {
-  return Array.isArray(arr) ? arr : Array.from(arr);
-};
+var arr = (function () {
+  var _arr = [];
 
-var arr = _toArray(nums).map(function (i) {
-  return i * i;
-});
+  for (var _iterator = nums[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
+    var i = _step.value;
+    _arr.push(i * i);
+  }
+
+  return _arr;
+})();

test/fixtures/transformation/es7-array-comprehension/this/expected.js

@@ -2,9 +2,16 @@
 
 function add() {
   var _this = this;
-  return [1, 2, 3].map(function (i) {
-    return i * _this.multiplier;
-  });
+  return (function () {
+    var _arr = [];
+
+    for (var _iterator = [1, 2, 3][Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
+      var i = _step.value;
+      _arr.push(i * _this.multiplier);
+    }
+
+    return _arr;
+  })();
 }
 
 add.call({ multiplier: 5 });

test/fixtures/transformation/optional-core-aliasing/es7-array-comprehensions/expected.js

@@ -1,15 +1,18 @@
 "use strict";
 
-var _toArray = function (arr) {
-  return Array.isArray(arr) ? arr : _core.Array.from(arr);
-};
-
 var _interopRequire = function (obj) {
   return obj && (obj["default"] || obj);
 };
 
 var _core = _interopRequire(require("core-js/library"));
 
-var arr = _toArray(nums).map(function (i) {
-  return i * i;
-});
+var arr = (function () {
+  var _arr = [];
+
+  for (var _iterator = _core.$for.getIterator(nums), _step; !(_step = _iterator.next()).done;) {
+    var i = _step.value;
+    _arr.push(i * i);
+  }
+
+  return _arr;
+})();