v1.13.2

CHANGELOG.md

@@ -1,3 +1,8 @@
+# 1.13.2
+
+ * Optimise `Array.from` usage by adding a helper method.
+ * Upgrade `acorn-6to5`.
+
 # 1.13.1
 
  * Fix constructor spread optimisation. Thanks [@zloirock](https://github.com/zloirock).

doc/caveats.md

@@ -13,7 +13,7 @@ ES7 features to work.
 ### Array comprehension/Array destructuring/Spread
 
 An [ES6 polyfill](polyfill.md) is required. More specifically a polyfill for
-`Array.from`.
+`Array.isArray` and `Array.from`.
 
 ## Classes
 

lib/6to5/file.js

@@ -19,7 +19,7 @@ function File(opts) {
 }
 
 File.declarations = ["extends", "class-props", "slice", "apply-constructor",
-                     "tagged-template-literal", "interop-require"];
+                     "tagged-template-literal", "interop-require", "to-array"];
 
 File.normaliseOptions = function (opts) {
   opts = _.cloneDeep(opts || {});
@@ -70,6 +70,14 @@ File.normaliseOptions = function (opts) {
   return opts;
 };
 
+File.prototype.toArray = function (node) {
+  if (t.isArrayExpression(node)) {
+    return node;
+  } else {
+    return t.callExpression(this.addDeclaration("to-array"), [node]);
+  }
+};
+
 File.prototype.getModuleFormatter = function (type) {
   var ModuleFormatter = _.isFunction(type) ? type : transform.moduleFormatters[type];
 

lib/6to5/templates/to-array.js

@@ -0,0 +1,3 @@
+(function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+});

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

@@ -2,21 +2,16 @@ var util = require("../../util");
 var t    = require("../../types");
 var _    = require("lodash");
 
-var single = function (node) {
+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 right = block.right;
-  if (!t.isArrayExpression(right)) {
-    right = util.template("array-from", { VALUE: right });
-  }
-
   var result = util.template(templateName, {
     STATEMENT: node.body,
     FILTER:    node.filter,
-    ARRAY:     right,
+    ARRAY:     file.toArray(block.right),
     KEY:       block.left
   });
 
@@ -79,7 +74,7 @@ exports.ComprehensionExpression = function (node, parent, file) {
   if (node.generator) return;
 
   if (node.blocks.length === 1) {
-    return single(node);
+    return single(node, file);
   } else {
     return multiple(node, file);
   }

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

@@ -1,6 +1,5 @@
-var util = require("../../util");
-var t    = require("../../types");
-var _    = require("lodash");
+var t = require("../../types");
+var _ = require("lodash");
 
 var buildVariableAssign = function (kind, id, init) {
   if (kind === false) {
@@ -40,9 +39,7 @@ var pushObjectPattern = function (opts, nodes, pattern, parentId) {
 var pushArrayPattern = function (opts, nodes, pattern, parentId) {
   var _parentId = opts.file.generateUidIdentifier("ref", opts.scope);
   nodes.push(t.variableDeclaration("var", [
-    t.variableDeclarator(_parentId, util.template("array-from", {
-      VALUE: parentId
-    }))
+    t.variableDeclarator(_parentId, opts.file.toArray(parentId))
   ]));
   parentId = _parentId;
 
@@ -52,9 +49,7 @@ var pushArrayPattern = function (opts, nodes, pattern, parentId) {
     var newPatternId;
 
     if (t.isSpreadElement(elem)) {
-      newPatternId = util.template("array-from", {
-        VALUE: parentId
-      });
+      newPatternId = opts.file.toArray(parentId);
 
       if (+i > 0) {
         newPatternId = t.callExpression(t.memberExpression(newPatternId, t.identifier("slice")), [t.literal(i)]);

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

@@ -1,15 +1,8 @@
-var util = require("../../util");
-var t    = require("../../types");
-var _    = require("lodash");
+var t = require("../../types");
+var _ = require("lodash");
 
-var getSpreadLiteral = function (spread) {
-  var literal = spread.argument;
-  if (!t.isArrayExpression(literal)) {
-    literal = util.template("array-from", {
-      VALUE: literal
-    });
-  }
-  return literal;
+var getSpreadLiteral = function (spread, file) {
+  return file.toArray(spread.argument);
 };
 
 var hasSpread = function (nodes) {
@@ -23,7 +16,7 @@ var hasSpread = function (nodes) {
   return has;
 };
 
-var build = function (props) {
+var build = function (props, file) {
   var nodes = [];
 
   var _props = [];
@@ -37,7 +30,7 @@ var build = function (props) {
   _.each(props, function (prop) {
     if (t.isSpreadElement(prop)) {
       push();
-      nodes.push(getSpreadLiteral(prop));
+      nodes.push(getSpreadLiteral(prop, file));
     } else {
       _props.push(prop);
     }
@@ -48,11 +41,11 @@ var build = function (props) {
   return nodes;
 };
 
-exports.ArrayExpression = function (node) {
+exports.ArrayExpression = function (node, parent, file) {
   var elements = node.elements;
   if (!hasSpread(elements)) return;
 
-  var nodes = build(elements);
+  var nodes = build(elements, file);
   var first = nodes.shift();
 
   if (!nodes.length) return first;
@@ -60,7 +53,7 @@ exports.ArrayExpression = function (node) {
   return t.callExpression(t.memberExpression(first, t.identifier("concat")), nodes);
 };
 
-exports.CallExpression = function (node) {
+exports.CallExpression = function (node, parent, file) {
   var args = node.arguments;
   if (!hasSpread(args)) return;
 
@@ -68,7 +61,7 @@ exports.CallExpression = function (node) {
 
   node.arguments = [];
 
-  var nodes = build(args);
+  var nodes = build(args, file);
   var first = nodes.shift();
 
   if (nodes.length) {
@@ -100,7 +93,7 @@ exports.NewExpression = function (node, parent, file) {
   var args = node.arguments;
   if (!hasSpread(args)) return;
 
-  var nodes = build(args);
+  var nodes = build(args, file);
   var first = nodes.shift();
 
   if (nodes.length) {

package.json

@@ -1,7 +1,7 @@
 {
   "name": "6to5",
   "description": "Turn ES6 code into readable vanilla ES5 with source maps",
-  "version": "1.13.1",
+  "version": "1.13.2",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://github.com/6to5/6to5",
   "repository": {
@@ -47,7 +47,7 @@
     "chokidar": "0.11.1",
     "source-map-support": "0.2.8",
     "esutils": "1.1.4",
-    "acorn-6to5": "0.9.1-3",
+    "acorn-6to5": "0.9.1-4",
     "estraverse": "1.8.0",
     "private": "0.1.6"
   },

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

@@ -1,6 +1,10 @@
 "use strict";
 
-var arr = Array.from(nums).filter(function (i) {
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
+var arr = _toArray(nums).filter(function (i) {
   return i > 1;
 }).map(function (i) {
   return i * i;

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

@@ -1,5 +1,9 @@
 "use strict";
 
-var arr = Array.from(nums).map(function (i) {
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
+var arr = _toArray(nums).map(function (i) {
   return i * i;
 });

test/fixtures/transformation/classes/accessing-super-class/expected.js

@@ -1,5 +1,9 @@
 "use strict";
 
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
 var _classProps = function (child, staticProps, instanceProps) {
   if (staticProps) Object.defineProperties(child, staticProps);
   if (instanceProps) Object.defineProperties(child.prototype, instanceProps);
@@ -24,11 +28,11 @@ var Test = (function (Foo) {
     Foo.prototype.test.call(this);
     foob(Foo);
 
-    Foo.call.apply(Foo, [this].concat(Array.from(arguments)));
-    Foo.call.apply(Foo, [this, "test"].concat(Array.from(arguments)));
+    Foo.call.apply(Foo, [this].concat(_toArray(arguments)));
+    Foo.call.apply(Foo, [this, "test"].concat(_toArray(arguments)));
 
-    Foo.prototype.test.call.apply(Foo.prototype, [this].concat(Array.from(arguments)));
-    Foo.prototype.test.call.apply(Foo.prototype, [this, "test"].concat(Array.from(arguments)));
+    Foo.prototype.test.call.apply(Foo.prototype, [this].concat(_toArray(arguments)));
+    Foo.prototype.test.call.apply(Foo.prototype, [this, "test"].concat(_toArray(arguments)));
   };
 
   _extends(Test, Foo);
@@ -38,8 +42,8 @@ var Test = (function (Foo) {
       writable: true,
       value: function () {
         Foo.foo.call(this);
-        Foo.foo.call.apply(Foo.foo, [this].concat(Array.from(arguments)));
-        Foo.foo.call.apply(Foo.foo, [this, "test"].concat(Array.from(arguments)));
+        Foo.foo.call.apply(Foo.foo, [this].concat(_toArray(arguments)));
+        Foo.foo.call.apply(Foo.foo, [this, "test"].concat(_toArray(arguments)));
       }
     }
   }, {
@@ -47,8 +51,8 @@ var Test = (function (Foo) {
       writable: true,
       value: function () {
         Foo.prototype.test.call(this);
-        Foo.prototype.test.call.apply(Foo.prototype.test, [this].concat(Array.from(arguments)));
-        Foo.prototype.test.call.apply(Foo.prototype.test, [this, "test"].concat(Array.from(arguments)));
+        Foo.prototype.test.call.apply(Foo.prototype.test, [this].concat(_toArray(arguments)));
+        Foo.prototype.test.call.apply(Foo.prototype.test, [this, "test"].concat(_toArray(arguments)));
       }
     }
   });

test/fixtures/transformation/constants/destructuring/expected.js

@@ -1,14 +1,18 @@
 "use strict";
 
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
 var _ref = [1, 2];
 
-var _ref2 = Array.from(_ref);
+var _ref2 = _toArray(_ref);
 
 var a = _ref2[0];
 var b = _ref2[1];
 var _ref3 = [3, 4];
 
-var _ref4 = Array.from(_ref3);
+var _ref4 = _toArray(_ref3);
 
 var c = _ref4[0];
 var d = _ref4[1];

test/fixtures/transformation/destructuring/array/expected.js

@@ -1,14 +1,18 @@
 "use strict";
 
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
 var _ref = ["hello", [", ", "junk"], ["world"]];
 
-var _ref2 = Array.from(_ref);
+var _ref2 = _toArray(_ref);
 
 var a = _ref2[0];
-var _ref3 = Array.from(_ref2[1]);
+var _ref3 = _toArray(_ref2[1]);
 
 var b = _ref3[0];
-var _ref4 = Array.from(_ref2[2]);
+var _ref4 = _toArray(_ref2[2]);
 
 var c = _ref4[0];
 var d = _ref2[3];

test/fixtures/transformation/destructuring/assignment-statement/expected.js

@@ -1,8 +1,12 @@
 "use strict";
 
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
 var _ref = f();
 
-var _ref2 = Array.from(_ref);
+var _ref2 = _toArray(_ref);
 
 a = _ref2[0];
 b = _ref2[1];

test/fixtures/transformation/destructuring/empty/expected.js

@@ -1,14 +1,18 @@
 "use strict";
 
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
 var _ref = ["foo", "hello", [", ", "junk"], ["world"]];
 
-var _ref2 = Array.from(_ref);
+var _ref2 = _toArray(_ref);
 
 var a = _ref2[1];
-var _ref3 = Array.from(_ref2[2]);
+var _ref3 = _toArray(_ref2[2]);
 
 var b = _ref3[0];
-var _ref4 = Array.from(_ref2[3]);
+var _ref4 = _toArray(_ref2[3]);
 
 var c = _ref4[0];
 var d = _ref2[4];

test/fixtures/transformation/destructuring/for-in/expected.js

@@ -1,7 +1,11 @@
 "use strict";
 
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
 for (var _ref in obj) {
-  var _ref2 = Array.from(_ref);
+  var _ref2 = _toArray(_ref);
 
   var name = _ref2[0];
   var value = _ref2[1];

test/fixtures/transformation/destructuring/for-of/expected.js

@@ -1,8 +1,12 @@
 "use strict";
 
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
 for (var _iterator = this.test.expectation.registers[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
   var _ref = _step.value;
-  var _ref2 = Array.from(_ref);
+  var _ref2 = _toArray(_ref);
 
   var name = _ref2[0];
   var before = _ref2[1];

test/fixtures/transformation/destructuring/member-expression/expected.js

@@ -1,8 +1,12 @@
 "use strict";
 
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
 var _ref = [1, 2];
 
-var _ref2 = Array.from(_ref);
+var _ref2 = _toArray(_ref);
 
 this.foo = _ref2[0];
 this.bar = _ref2[1];

test/fixtures/transformation/destructuring/mixed/expected.js

@@ -1,10 +1,14 @@
 "use strict";
 
-var _ref = Array.from(rect.topLeft);
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
+var _ref = _toArray(rect.topLeft);
 
 var x1 = _ref[0];
 var y1 = _ref[1];
-var _ref2 = Array.from(rect.bottomRight);
+var _ref2 = _toArray(rect.bottomRight);
 
 var x2 = _ref2[0];
 var y2 = _ref2[1];

test/fixtures/transformation/destructuring/parameters/expected.js

@@ -1,5 +1,9 @@
 "use strict";
 
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
 function somethingAdvanced(_ref) {
   var x1 = _ref.topLeft.x;
   var y1 = _ref.topLeft.y;
@@ -16,12 +20,12 @@ function unpackObject(_ref2) {
 console.log(unpackObject({ title: "title", author: "author" }));
 
 var unpackArray = function (_ref3, _ref5) {
-  var _ref4 = Array.from(_ref3);
+  var _ref4 = _toArray(_ref3);
 
   var a = _ref4[0];
   var b = _ref4[1];
   var c = _ref4[2];
-  var _ref6 = Array.from(_ref5);
+  var _ref6 = _toArray(_ref5);
 
   var x = _ref6[0];
   var y = _ref6[1];

test/fixtures/transformation/destructuring/spread/expected.js

@@ -1,11 +1,15 @@
 "use strict";
 
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
 var isSorted = function (_ref) {
-  var _ref2 = Array.from(_ref);
+  var _ref2 = _toArray(_ref);
 
   var x = _ref2[0];
   var y = _ref2[1];
-  var wow = Array.from(_ref2).slice(2);
+  var wow = _toArray(_ref2).slice(2);
 
   if (!zs.length) return true;
   if (y > x) return isSorted(zs);

test/fixtures/transformation/spread/arguments/expected.js

@@ -1,7 +1,11 @@
 "use strict";
 
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
 function foo() {
-  return bar.apply(null, ["test"].concat(Array.from(arguments)));
+  return bar.apply(null, ["test"].concat(_toArray(arguments)));
 }
 
 function bar(one, two, three) {

test/fixtures/transformation/spread/array-literal-first/expected.js

@@ -1,3 +1,7 @@
 "use strict";
 
-var lyrics = Array.from(parts).concat(["head", "and", "toes"]);
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
+var lyrics = _toArray(parts).concat(["head", "and", "toes"]);

test/fixtures/transformation/spread/array-literal-middle/expected.js

@@ -1,3 +1,7 @@
 "use strict";
 
-var a = [b].concat(Array.from(c), [d]);
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
+var a = [b].concat(_toArray(c), [d]);

test/fixtures/transformation/spread/array-literal-multiple/expected.js

@@ -1,3 +1,7 @@
 "use strict";
 
-var a = [b].concat(Array.from(c), [d, e], Array.from(f));
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
+var a = [b].concat(_toArray(c), [d, e], _toArray(f));

test/fixtures/transformation/spread/array-literals/expected.js

@@ -1,3 +1,7 @@
 "use strict";
 
-var lyrics = ["head", "and", "toes"].concat(Array.from(parts));
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
+var lyrics = ["head", "and", "toes"].concat(_toArray(parts));

test/fixtures/transformation/spread/contexted-computed-method-call-multiple-args/expected.js

@@ -1,3 +1,7 @@
 "use strict";
 
-obj[method].apply(obj, [foo, bar].concat(Array.from(args)));
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
+obj[method].apply(obj, [foo, bar].concat(_toArray(args)));

test/fixtures/transformation/spread/contexted-computed-method-call-single-arg/expected.js

@@ -1,3 +1,7 @@
 "use strict";
 
-obj[method].apply(obj, Array.from(args));
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
+obj[method].apply(obj, _toArray(args));

test/fixtures/transformation/spread/contexted-method-call-multiple-args/expected.js

@@ -1,4 +1,8 @@
 "use strict";
 
-foob.add.apply(foob, [foo, bar].concat(Array.from(numbers)));
-foob.test.add.apply(foob.test, [foo, bar].concat(Array.from(numbers)));
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
+foob.add.apply(foob, [foo, bar].concat(_toArray(numbers)));
+foob.test.add.apply(foob.test, [foo, bar].concat(_toArray(numbers)));

test/fixtures/transformation/spread/contexted-method-call-single-arg/expected.js

@@ -1,4 +1,8 @@
 "use strict";
 
-foob.add.apply(foob, Array.from(numbers));
-foob.test.add.apply(foob.test, Array.from(numbers));
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
+foob.add.apply(foob, _toArray(numbers));
+foob.test.add.apply(foob.test, _toArray(numbers));

test/fixtures/transformation/spread/method-call-first/expected.js

@@ -1,3 +1,7 @@
 "use strict";
 
-add.apply(null, Array.from(numbers).concat([foo, bar]));
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
+add.apply(null, _toArray(numbers).concat([foo, bar]));

test/fixtures/transformation/spread/method-call-middle/expected.js

@@ -1,3 +1,7 @@
 "use strict";
 
-add.apply(null, [foo].concat(Array.from(numbers), [bar]));
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
+add.apply(null, [foo].concat(_toArray(numbers), [bar]));

test/fixtures/transformation/spread/method-call-multiple-args/expected.js

@@ -1,3 +1,7 @@
 "use strict";
 
-add.apply(null, [foo, bar].concat(Array.from(numbers)));
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
+add.apply(null, [foo, bar].concat(_toArray(numbers)));

test/fixtures/transformation/spread/method-call-multiple/expected.js

@@ -1,3 +1,7 @@
 "use strict";
 
-add.apply(null, [foo].concat(Array.from(numbers), [bar, what], Array.from(test)));
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
+add.apply(null, [foo].concat(_toArray(numbers), [bar, what], _toArray(test)));

test/fixtures/transformation/spread/method-call-single-arg/expected.js

@@ -1,3 +1,7 @@
 "use strict";
 
-add.apply(null, Array.from(numbers));
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
+add.apply(null, _toArray(numbers));

test/fixtures/transformation/spread/new-expression/expected.js

@@ -8,5 +8,9 @@ var _applyConstructor = function (Constructor, args) {
   return result != null && (typeof result == "object" || typeof result == "function") ? result : instance;
 };
 
-_applyConstructor(Numbers, Array.from(nums));
-_applyConstructor(Numbers, [1].concat(Array.from(nums)));
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
+_applyConstructor(Numbers, _toArray(nums));
+_applyConstructor(Numbers, [1].concat(_toArray(nums)));

test/fixtures/transformation/spread/single/expected.js

@@ -1,3 +1,7 @@
 "use strict";
 
-Array.from(foo);
+var _toArray = function (arr) {
+  return Array.isArray(arr) ? arr : Array.from(arr);
+};
+
+_toArray(foo);