Don't use Array.from for array-like objects

packages/babel-helpers/src/helpers.js

@@ -909,7 +909,7 @@ helpers.slicedToArray = helper("7.0.0-beta.0")`
     return (
       arrayWithHoles(arr) ||
       iterableToArrayLimit(arr, i) ||
-      unsupportedIterableToArray(arr) ||
+      unsupportedIterableToArray(arr, i) ||
       nonIterableRest()
     );
   }
@@ -925,7 +925,7 @@ helpers.slicedToArrayLoose = helper("7.0.0-beta.0")`
     return (
       arrayWithHoles(arr) ||
       iterableToArrayLimitLoose(arr, i) ||
-      unsupportedIterableToArray(arr) ||
+      unsupportedIterableToArray(arr, i) ||
       nonIterableRest()
     );
   }
@@ -964,11 +964,10 @@ helpers.toConsumableArray = helper("7.0.0-beta.0")`
 `;
 
 helpers.arrayWithoutHoles = helper("7.0.0-beta.0")`
+  import arrayLikeToArray from "arrayLikeToArray";
+
   export default function _arrayWithoutHoles(arr) {
-    if (Array.isArray(arr)) {
-      for (var i = 0, arr2 = new Array(arr.length); i < arr.length; i++) arr2[i] = arr[i];
-      return arr2;
-    }
+    if (Array.isArray(arr)) return arrayLikeToArray(arr);
   }
 `;
 
@@ -1035,17 +1034,24 @@ helpers.iterableToArrayLimitLoose = helper("7.0.0-beta.0")`
 `;
 
 helpers.unsupportedIterableToArray = helper("7.9.0")`
-  export default function _unsupportedIterableToArray(o) {
+  import arrayLikeToArray from "arrayLikeToArray";
+
+  export default function _unsupportedIterableToArray(o, minLen) {
     if (!o) return;
-    if (typeof o === "string") return Array.from(o);
+    if (typeof o === "string") return arrayLikeToArray(o, minLen);
     var n = Object.prototype.toString.call(o).slice(8, -1);
     if (n === "Object" && o.constructor) n = o.constructor.name;
-    if (
-      n === "Arguments" ||
-      n === "Map" ||
-      n === "Set" ||
-      /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)
-    ) return Array.from(o);
+    if (n === "Map" || n === "Set") return Array.from(n);
+    if (n === "Arguments" || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n))
+      return arrayLikeToArray(o, minLen);
+  }
+`;
+
+helpers.arrayLikeToArray = helper("7.9.0")`
+  export default function _arrayLikeToArray(arr, len) {
+    if (len == null || len > arr.length) len = arr.length;
+    for (var i = 0, arr2 = new Array(len); i < len; i++) arr2[i] = arr[i];
+    return arr2;
   }
 `;
 

packages/babel-plugin-transform-modules-commonjs/test/fixtures/regression/T7199/output.js

@@ -4,11 +4,13 @@ var _foo = _interopRequireDefault(require("foo"));
 
 function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { "default": obj }; }
 
-function _slicedToArray(arr, i) { return _arrayWithHoles(arr) || _iterableToArrayLimit(arr, i) || _unsupportedIterableToArray(arr) || _nonIterableRest(); }
+function _slicedToArray(arr, i) { return _arrayWithHoles(arr) || _iterableToArrayLimit(arr, i) || _unsupportedIterableToArray(arr, i) || _nonIterableRest(); }
 
 function _nonIterableRest() { throw new TypeError("Invalid attempt to destructure non-iterable instance.\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method."); }
 
-function _unsupportedIterableToArray(o) { if (!o) return; if (typeof o === "string") return Array.from(o); var n = Object.prototype.toString.call(o).slice(8, -1); if (n === "Object" && o.constructor) n = o.constructor.name; if (n === "Arguments" || n === "Map" || n === "Set" || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return Array.from(o); }
+function _unsupportedIterableToArray(o, minLen) { if (!o) return; if (typeof o === "string") return _arrayLikeToArray(o, minLen); var n = Object.prototype.toString.call(o).slice(8, -1); if (n === "Object" && o.constructor) n = o.constructor.name; if (n === "Map" || n === "Set") return Array.from(n); if (n === "Arguments" || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen); }
+
+function _arrayLikeToArray(arr, len) { if (len == null || len > arr.length) len = arr.length; for (var i = 0, arr2 = new Array(len); i < len; i++) arr2[i] = arr[i]; return arr2; }
 
 function _iterableToArrayLimit(arr, i) { if (typeof Symbol === "undefined" || !(Symbol.iterator in Object(arr))) return; var _arr = []; var _n = true; var _d = false; var _e = undefined; try { for (var _i = arr[Symbol.iterator](), _s; !(_n = (_s = _i.next()).done); _n = true) { _arr.push(_s.value); if (i && _arr.length === i) break; } } catch (err) { _d = true; _e = err; } finally { try { if (!_n && _i["return"] != null) _i["return"](); } finally { if (_d) throw _e; } } return _arr; }
 

packages/babel-preset-env/test/fixtures/preset-options/browserslist-defaults-not-ie/output.js

@@ -1,10 +1,12 @@
 "use strict";
 
-function _slicedToArray(arr, i) { return _arrayWithHoles(arr) || _iterableToArrayLimit(arr, i) || _unsupportedIterableToArray(arr) || _nonIterableRest(); }
+function _slicedToArray(arr, i) { return _arrayWithHoles(arr) || _iterableToArrayLimit(arr, i) || _unsupportedIterableToArray(arr, i) || _nonIterableRest(); }
 
 function _nonIterableRest() { throw new TypeError("Invalid attempt to destructure non-iterable instance.\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method."); }
 
-function _unsupportedIterableToArray(o) { if (!o) return; if (typeof o === "string") return Array.from(o); var n = Object.prototype.toString.call(o).slice(8, -1); if (n === "Object" && o.constructor) n = o.constructor.name; if (n === "Arguments" || n === "Map" || n === "Set" || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return Array.from(o); }
+function _unsupportedIterableToArray(o, minLen) { if (!o) return; if (typeof o === "string") return _arrayLikeToArray(o, minLen); var n = Object.prototype.toString.call(o).slice(8, -1); if (n === "Object" && o.constructor) n = o.constructor.name; if (n === "Map" || n === "Set") return Array.from(n); if (n === "Arguments" || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen); }
+
+function _arrayLikeToArray(arr, len) { if (len == null || len > arr.length) len = arr.length; for (var i = 0, arr2 = new Array(len); i < len; i++) { arr2[i] = arr[i]; } return arr2; }
 
 function _iterableToArrayLimit(arr, i) { if (typeof Symbol === "undefined" || !(Symbol.iterator in Object(arr))) return; var _arr = []; var _n = true; var _d = false; var _e = undefined; try { for (var _i = arr[Symbol.iterator](), _s; !(_n = (_s = _i.next()).done); _n = true) { _arr.push(_s.value); if (i && _arr.length === i) break; } } catch (err) { _d = true; _e = err; } finally { try { if (!_n && _i["return"] != null) _i["return"](); } finally { if (_d) throw _e; } } return _arr; }
 

packages/babel-preset-env/test/fixtures/sanity/block-scoping-for-of/output.js

@@ -1,8 +1,10 @@
-function _slicedToArray(arr, i) { return _arrayWithHoles(arr) || _iterableToArrayLimit(arr, i) || _unsupportedIterableToArray(arr) || _nonIterableRest(); }
+function _slicedToArray(arr, i) { return _arrayWithHoles(arr) || _iterableToArrayLimit(arr, i) || _unsupportedIterableToArray(arr, i) || _nonIterableRest(); }
 
 function _nonIterableRest() { throw new TypeError("Invalid attempt to destructure non-iterable instance.\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method."); }
 
-function _unsupportedIterableToArray(o) { if (!o) return; if (typeof o === "string") return Array.from(o); var n = Object.prototype.toString.call(o).slice(8, -1); if (n === "Object" && o.constructor) n = o.constructor.name; if (n === "Arguments" || n === "Map" || n === "Set" || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return Array.from(o); }
+function _unsupportedIterableToArray(o, minLen) { if (!o) return; if (typeof o === "string") return _arrayLikeToArray(o, minLen); var n = Object.prototype.toString.call(o).slice(8, -1); if (n === "Object" && o.constructor) n = o.constructor.name; if (n === "Map" || n === "Set") return Array.from(n); if (n === "Arguments" || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen); }
+
+function _arrayLikeToArray(arr, len) { if (len == null || len > arr.length) len = arr.length; for (var i = 0, arr2 = new Array(len); i < len; i++) { arr2[i] = arr[i]; } return arr2; }
 
 function _iterableToArrayLimit(arr, i) { if (typeof Symbol === "undefined" || !(Symbol.iterator in Object(arr))) return; var _arr = []; var _n = true; var _d = false; var _e = undefined; try { for (var _i = arr[Symbol.iterator](), _s; !(_n = (_s = _i.next()).done); _n = true) { _arr.push(_s.value); if (i && _arr.length === i) break; } } catch (err) { _d = true; _e = err; } finally { try { if (!_n && _i["return"] != null) _i["return"](); } finally { if (_d) throw _e; } } return _arr; }