Fix: default rest argument array elements as undefined

packages/babel-plugin-transform-parameters/src/rest.ts

@@ -1,12 +1,8 @@
 import { template, types as t } from "@babel/core";
 
 const buildRest = template(`
-  for (var LEN = ARGUMENTS.length,
-           ARRAY = new Array(ARRAY_LEN),
-           KEY = START;
-       KEY < LEN;
-       KEY++) {
-    ARRAY[ARRAY_KEY] = ARGUMENTS[KEY];
+  for (var ARGS = ARGUMENTS, LEN = ARGS.length, ARRAY = new Array(ARRAY_LEN), KEY = START; KEY < LEN; KEY++) {
+    ARRAY[ARRAY_KEY] = ARGS[KEY];
   }
 `);
 
@@ -334,7 +330,10 @@ export default function convertFunctionRest(path) {
     arrLen = t.identifier(len.name);
   }
 
+  const args = scope.generateUidIdentifier("args");
+
   const loop = buildRest({
+    ARGS: args,
     ARGUMENTS: argsId,
     ARRAY_KEY: arrKey,
     ARRAY_LEN: arrLen,

packages/babel-plugin-transform-parameters/test/fixtures/assumption-ignoreFunctionLength/destructuring-rest/output.js

@@ -7,8 +7,8 @@ function t(x, _ref) {
   var a = _ref.a,
       b = _ref.b;
 
-  for (var _len = arguments.length, args = new Array(_len > 2 ? _len - 2 : 0), _key = 2; _key < _len; _key++) {
-    args[_key - 2] = arguments[_key];
+  for (var _args = arguments, _len = _args.length, args = new Array(_len > 2 ? _len - 2 : 0), _key = 2; _key < _len; _key++) {
+    args[_key - 2] = _args[_key];
   }
 
   console.log(x, a, b, args);

packages/babel-plugin-transform-parameters/test/fixtures/parameters/default-arguments/exec.js

@@ -0,0 +1,4 @@
+function func(...arguments) {
+    return arguments;
+}
+expect(func(1, 2, 3)).toStrictEqual([1, 2, 3])

packages/babel-plugin-transform-parameters/test/fixtures/parameters/default-arguments/input.js

@@ -0,0 +1,4 @@
+function func(...arguments) {
+    console.log(arguments); // [1, 2, 3]
+}
+func(1, 2, 3);

packages/babel-plugin-transform-parameters/test/fixtures/parameters/default-arguments/output.js

@@ -0,0 +1,9 @@
+function func() {
+  for (var _args = arguments, _len = _args.length, arguments = new Array(_len), _key = 0; _key < _len; _key++) {
+    arguments[_key] = _args[_key];
+  }
+
+  console.log(arguments); // [1, 2, 3]
+}
+
+func(1, 2, 3);

packages/babel-plugin-transform-parameters/test/fixtures/parameters/default-rest/output.js

@@ -17,8 +17,8 @@ rest2(undefined, 2);
 function rest3() {
   var b = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : a;
 
-  for (var _len = arguments.length, a = new Array(_len > 1 ? _len - 1 : 0), _key = 1; _key < _len; _key++) {
-    a[_key - 1] = arguments[_key];
+  for (var _args = arguments, _len = _args.length, a = new Array(_len > 1 ? _len - 1 : 0), _key = 1; _key < _len; _key++) {
+    a[_key - 1] = _args[_key];
   }
 
   expect(a).toHaveLength(1);

packages/babel-plugin-transform-parameters/test/fixtures/parameters/destructuring-rest/output.js

@@ -6,8 +6,8 @@ function t() {
       a = _ref.a,
       b = _ref.b;
 
-  for (var _len = arguments.length, args = new Array(_len > 2 ? _len - 2 : 0), _key = 2; _key < _len; _key++) {
-    args[_key - 2] = arguments[_key];
+  for (var _args = arguments, _len = _args.length, args = new Array(_len > 2 ? _len - 2 : 0), _key = 2; _key < _len; _key++) {
+    args[_key - 2] = _args[_key];
   }
 
   console.log(x, a, b, args);

packages/babel-plugin-transform-parameters/test/fixtures/parameters/regression-4333/output.js

@@ -1,8 +1,8 @@
 var args = 'bar';
 
 function foo() {
-  for (var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
-    args[_key] = arguments[_key];
+  for (var _args = arguments, _len = _args.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
+    args[_key] = _args[_key];
   }
 
   return args;

packages/babel-plugin-transform-parameters/test/fixtures/parameters/regression-4634/output.js

@@ -1,6 +1,6 @@
 let oneOf = function () {
-  for (var _len = arguments.length, nodes = new Array(_len), _key = 0; _key < _len; _key++) {
-    nodes[_key] = arguments[_key];
+  for (var _args = arguments, _len = _args.length, nodes = new Array(_len), _key = 0; _key < _len; _key++) {
+    nodes[_key] = _args[_key];
   }
 
   if (nodes.length === 1) {

packages/babel-plugin-transform-parameters/test/fixtures/parameters/rest-arguments-deoptimisation/output.js

@@ -1,6 +1,6 @@
 function x() {
-  for (var _len = arguments.length, rest = new Array(_len), _key = 0; _key < _len; _key++) {
-    rest[_key] = arguments[_key];
+  for (var _args = arguments, _len = _args.length, rest = new Array(_len), _key = 0; _key < _len; _key++) {
+    rest[_key] = _args[_key];
   }
 
   arguments;

packages/babel-plugin-transform-parameters/test/fixtures/parameters/rest-arrow-functions/output.js

@@ -24,8 +24,8 @@ var somefun = function () {
 };
 
 function demo1() {
-  for (var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
-    args[_key] = arguments[_key];
+  for (var _args = arguments, _len = _args.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
+    args[_key] = _args[_key];
   }
 
   return function (i) {
@@ -36,8 +36,8 @@ function demo1() {
 var x = function () {
   if (noNeedToWork) return 0;
 
-  for (var _len2 = arguments.length, rest = new Array(_len2), _key2 = 0; _key2 < _len2; _key2++) {
-    rest[_key2] = arguments[_key2];
+  for (var _args2 = arguments, _len2 = _args2.length, rest = new Array(_len2), _key2 = 0; _key2 < _len2; _key2++) {
+    rest[_key2] = _args2[_key2];
   }
 
   return rest;
@@ -46,8 +46,8 @@ var x = function () {
 var innerclassproperties = function () {
   var _class, _temp;
 
-  for (var _len3 = arguments.length, args = new Array(_len3), _key3 = 0; _key3 < _len3; _key3++) {
-    args[_key3] = arguments[_key3];
+  for (var _args3 = arguments, _len3 = _args3.length, args = new Array(_len3), _key3 = 0; _key3 < _len3; _key3++) {
+    args[_key3] = _args3[_key3];
   }
 
   return _temp = _class = function _class() {

packages/babel-plugin-transform-parameters/test/fixtures/parameters/rest-async-arrow-functions/output.js

@@ -13,8 +13,8 @@ var x = /*#__PURE__*/function () {
   var _ref2 = babelHelpers.asyncToGenerator(function* () {
     if (noNeedToWork) return 0;
 
-    for (var _len = arguments.length, rest = new Array(_len), _key = 0; _key < _len; _key++) {
-      rest[_key] = arguments[_key];
+    for (var _args = arguments, _len = _args.length, rest = new Array(_len), _key = 0; _key < _len; _key++) {
+      rest[_key] = _args[_key];
     }
 
     return rest;

packages/babel-plugin-transform-parameters/test/fixtures/parameters/rest-binding-deoptimisation/output.js

@@ -1,6 +1,6 @@
 var deepAssign = function () {
-  for (var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
-    args[_key] = arguments[_key];
+  for (var _args = arguments, _len = _args.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
+    args[_key] = _args[_key];
   }
 
   return args = [];

packages/babel-plugin-transform-parameters/test/fixtures/parameters/rest-deepest-common-ancestor-earliest-child/output.js

@@ -2,8 +2,8 @@
 function r() {
   if (noNeedToWork) return 0;
 
-  for (var _len = arguments.length, rest = new Array(_len), _key = 0; _key < _len; _key++) {
-    rest[_key] = arguments[_key];
+  for (var _args = arguments, _len = _args.length, rest = new Array(_len), _key = 0; _key < _len; _key++) {
+    rest[_key] = _args[_key];
   }
 
   return rest;
@@ -13,8 +13,8 @@ function r() {
 function r() {
   if (noNeedToWork) return 0;
 
-  for (var _len2 = arguments.length, rest = new Array(_len2), _key2 = 0; _key2 < _len2; _key2++) {
-    rest[_key2] = arguments[_key2];
+  for (var _args2 = arguments, _len2 = _args2.length, rest = new Array(_len2), _key2 = 0; _key2 < _len2; _key2++) {
+    rest[_key2] = _args2[_key2];
   }
 
   rest;
@@ -25,8 +25,8 @@ function r() {
 function r() {
   if (noNeedToWork) return 0;
 
-  for (var _len3 = arguments.length, rest = new Array(_len3), _key3 = 0; _key3 < _len3; _key3++) {
-    rest[_key3] = arguments[_key3];
+  for (var _args3 = arguments, _len3 = _args3.length, rest = new Array(_len3), _key3 = 0; _key3 < _len3; _key3++) {
+    rest[_key3] = _args3[_key3];
   }
 
   if (true) {
@@ -39,8 +39,8 @@ function r() {
 
 function r() {
   if (true) {
-    for (var _len4 = arguments.length, rest = new Array(_len4), _key4 = 0; _key4 < _len4; _key4++) {
-      rest[_key4] = arguments[_key4];
+    for (var _args4 = arguments, _len4 = _args4.length, rest = new Array(_len4), _key4 = 0; _key4 < _len4; _key4++) {
+      rest[_key4] = _args4[_key4];
     }
 
     if (true) {
@@ -55,8 +55,8 @@ function r() {
 function r() {
   if (noNeedToWork) return 0;
 
-  for (var _len5 = arguments.length, rest = new Array(_len5), _key5 = 0; _key5 < _len5; _key5++) {
-    rest[_key5] = arguments[_key5];
+  for (var _args5 = arguments, _len5 = _args5.length, rest = new Array(_len5), _key5 = 0; _key5 < _len5; _key5++) {
+    rest[_key5] = _args5[_key5];
   }
 
   if (lol) rest;
@@ -65,8 +65,8 @@ function r() {
 
 
 function a() {
-  for (var _len6 = arguments.length, args = new Array(_len6), _key6 = 0; _key6 < _len6; _key6++) {
-    args[_key6] = arguments[_key6];
+  for (var _args6 = arguments, _len6 = _args6.length, args = new Array(_len6), _key6 = 0; _key6 < _len6; _key6++) {
+    args[_key6] = _args6[_key6];
   }
 
   return function () {
@@ -78,8 +78,8 @@ function a() {
 
 
 function runQueue(queue) {
-  for (var _len7 = arguments.length, args = new Array(_len7 > 1 ? _len7 - 1 : 0), _key7 = 1; _key7 < _len7; _key7++) {
-    args[_key7 - 1] = arguments[_key7];
+  for (var _args7 = arguments, _len7 = _args7.length, args = new Array(_len7 > 1 ? _len7 - 1 : 0), _key7 = 1; _key7 < _len7; _key7++) {
+    args[_key7 - 1] = _args7[_key7];
   }
 
   for (var i = 0; i < queue.length; i++) {
@@ -90,8 +90,8 @@ function runQueue(queue) {
 
 function runQueue(queue) {
   if (foo) {
-    for (var _len8 = arguments.length, args = new Array(_len8 > 1 ? _len8 - 1 : 0), _key8 = 1; _key8 < _len8; _key8++) {
-      args[_key8 - 1] = arguments[_key8];
+    for (var _args8 = arguments, _len8 = _args8.length, args = new Array(_len8 > 1 ? _len8 - 1 : 0), _key8 = 1; _key8 < _len8; _key8++) {
+      args[_key8 - 1] = _args8[_key8];
     }
 
     for (var i = 0; i < queue.length; i++) {
@@ -103,8 +103,8 @@ function runQueue(queue) {
 function r() {
   if (noNeedToWork) return 0;
 
-  for (var _len9 = arguments.length, rest = new Array(_len9), _key9 = 0; _key9 < _len9; _key9++) {
-    rest[_key9] = arguments[_key9];
+  for (var _args9 = arguments, _len9 = _args9.length, rest = new Array(_len9), _key9 = 0; _key9 < _len9; _key9++) {
+    rest[_key9] = _args9[_key9];
   }
 
   var _x = x;

packages/babel-plugin-transform-parameters/test/fixtures/parameters/rest-length/output.js

@@ -6,8 +6,8 @@ var t = function (f) {
 };
 
 function t(f) {
-  for (var _len = arguments.length, items = new Array(_len > 1 ? _len - 1 : 0), _key = 1; _key < _len; _key++) {
-    items[_key - 1] = arguments[_key];
+  for (var _args = arguments, _len = _args.length, items = new Array(_len > 1 ? _len - 1 : 0), _key = 1; _key < _len; _key++) {
+    items[_key - 1] = _args[_key];
   }
 
   items;