replace slice with a loop in rest parameters

lib/6to5/transformation/templates/rest.js

@@ -0,0 +1,3 @@
+for (var KEY = START; KEY < ARGUMENTS.length; KEY++) {
+  ARRAY[$__0] = ARGUMENTS[KEY];
+}

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

@@ -1,6 +1,7 @@
-var t = require("../../types");
+var util = require("../../util");
+var t    = require("../../types");
 
-exports.Function = function (node, parent, file) {
+exports.Function = function (node, parent, file, scope) {
   if (!node.rest) return;
 
   var rest = node.rest;
@@ -8,15 +9,19 @@ exports.Function = function (node, parent, file) {
 
   t.ensureBlock(node);
 
-  var call = file.toArray(t.identifier("arguments"));
+  var argsId = t.identifier("arguments");
+  argsId._ignoreAliasFunctions = true;
 
-  if (node.params.length) {
-    call.arguments.push(t.literal(node.params.length));
-  }
+  node.body.body.unshift(
+    t.variableDeclaration("var", [
+      t.variableDeclarator(rest, t.arrayExpression([]))
+    ]),
 
-  call._ignoreAliasFunctions = true;
-
-  node.body.body.unshift(t.variableDeclaration("var", [
-    t.variableDeclarator(rest, call)
-  ]));
+    util.template("rest", {
+      ARGUMENTS: argsId,
+      START: t.literal(node.params.length),
+      ARRAY: rest,
+      KEY: file.generateUidIdentifier("key")
+    })
+  );
 };

test/fixtures/transformation/es6-rest-parameters/arrow-functions/expected.js

@@ -1,6 +1,9 @@
 "use strict";
 
-var _slice = Array.prototype.slice;
 var concat = function () {
-  var arrs = _slice.call(arguments);
+  var arrs = [];
+
+  for (var _key = 0; _key < arguments.length; _key++) {
+    arrs[$__0] = arguments[_key];
+  }
 };

test/fixtures/transformation/es6-rest-parameters/multiple/expected.js

@@ -1,10 +1,17 @@
 "use strict";
 
-var _slice = Array.prototype.slice;
 var t = function (f) {
-  var items = _slice.call(arguments, 1);
+  var items = [];
+
+  for (var _key = 1; _key < arguments.length; _key++) {
+    items[$__0] = arguments[_key];
+  }
 };
 
 function t(f) {
-  var items = _slice.call(arguments, 1);
+  var items = [];
+
+  for (var _key2 = 1; _key2 < arguments.length; _key2++) {
+    items[$__0] = arguments[_key2];
+  }
 }

test/fixtures/transformation/es6-rest-parameters/single/expected.js

@@ -1,10 +1,17 @@
 "use strict";
 
-var _slice = Array.prototype.slice;
 var t = function () {
-  var items = _slice.call(arguments);
+  var items = [];
+
+  for (var _key = 0; _key < arguments.length; _key++) {
+    items[$__0] = arguments[_key];
+  }
 };
 
 function t() {
-  var items = _slice.call(arguments);
+  var items = [];
+
+  for (var _key2 = 0; _key2 < arguments.length; _key2++) {
+    items[$__0] = arguments[_key2];
+  }
 }

test/fixtures/transformation/es6-spread/arguments-concat/expected.js

@@ -2,7 +2,7 @@
 
 var _slice = Array.prototype.slice;
 function foo() {
-  return bar.apply(null, ["test"].concat(_slice.call(arguments)));
+  return bar.apply(undefined, ["test"].concat(_slice.call(arguments)));
 }
 
 function bar(one, two, three) {

test/fixtures/transformation/es6-spread/arguments/expected.js

@@ -1,7 +1,7 @@
 "use strict";
 
 function foo() {
-  return bar.apply(null, arguments);
+  return bar.apply(undefined, arguments);
 }
 
 function bar(one, two, three) {

test/fixtures/transformation/es6-spread/method-call-array-literal/expected.js

@@ -1,3 +1,3 @@
 "use strict";
 
-f.apply(null, [1, 2, 3]);
+f.apply(undefined, [1, 2, 3]);

test/fixtures/transformation/es6-spread/method-call-first/expected.js

@@ -4,4 +4,4 @@ var _toArray = function (arr) {
   return Array.isArray(arr) ? arr : Array.from(arr);
 };
 
-add.apply(null, _toArray(numbers).concat([foo, bar]));
+add.apply(undefined, _toArray(numbers).concat([foo, bar]));

test/fixtures/transformation/es6-spread/method-call-middle/expected.js

@@ -4,4 +4,4 @@ var _toArray = function (arr) {
   return Array.isArray(arr) ? arr : Array.from(arr);
 };
 
-add.apply(null, [foo].concat(_toArray(numbers), [bar]));
+add.apply(undefined, [foo].concat(_toArray(numbers), [bar]));

test/fixtures/transformation/es6-spread/method-call-multiple-args/expected.js

@@ -4,4 +4,4 @@ var _toArray = function (arr) {
   return Array.isArray(arr) ? arr : Array.from(arr);
 };
 
-add.apply(null, [foo, bar].concat(_toArray(numbers)));
+add.apply(undefined, [foo, bar].concat(_toArray(numbers)));

test/fixtures/transformation/es6-spread/method-call-multiple/expected.js

@@ -4,4 +4,4 @@ var _toArray = function (arr) {
   return Array.isArray(arr) ? arr : Array.from(arr);
 };
 
-add.apply(null, [foo].concat(_toArray(numbers), [bar, what], _toArray(test)));
+add.apply(undefined, [foo].concat(_toArray(numbers), [bar, what], _toArray(test)));

test/fixtures/transformation/es6-spread/method-call-single-arg/expected.js

@@ -4,4 +4,4 @@ var _toArray = function (arr) {
   return Array.isArray(arr) ? arr : Array.from(arr);
 };
 
-add.apply(null, _toArray(numbers));
+add.apply(undefined, _toArray(numbers));

test/fixtures/transformation/misc/custom-runtime/actual.js

@@ -1,3 +1,3 @@
-function foo(...test) {
-
+function foo() {
+  test("bar", ...arguments);
 }

test/fixtures/transformation/misc/custom-runtime/expected.js

@@ -1,5 +1,5 @@
 "use strict";
 
 function foo() {
-  var test = customNamespace.slice.call(arguments);
+  test.apply(undefined, ["bar"].concat(customNamespace.slice.call(arguments)));
 }

test/fixtures/transformation/misc/runtime/actual.js

@@ -1,3 +1,3 @@
-function foo(...test) {
-
+function foo() {
+  test("bar", ...arguments);
 }

test/fixtures/transformation/misc/runtime/expected.js

@@ -1,5 +1,5 @@
 "use strict";
 
 function foo() {
-  var test = to5Runtime.slice.call(arguments);
+  test.apply(undefined, ["bar"].concat(to5Runtime.slice.call(arguments)));
 }