Extract for-of iterator handling to a helper (#11262)

* Extract for-of iterator handling to a helper

Dis greatly recudes the code size when for-of is used multiple times across the
codebase. Also, makes it easier to read what's happening in a compiled loop.

* Unify spec and loose code

* Legacy implementation fallback

* Update tmp var name

* Updates from review and after rebase

packages/babel-helpers/src/helpers.js

@@ -1036,6 +1036,61 @@ helpers.nonIterableRest = helper("7.0.0-beta.0")`
   }
 `;
 
+helpers.createForOfIteratorHelper = helper("7.9.0")`
+  // s: start (create the iterator)
+  // n: next
+  // e: error (called whenever something throws)
+  // f: finish (always called at the end)
+
+  export default function _createForOfIteratorHelper(o) {
+    if (typeof Symbol === "undefined" || o[Symbol.iterator] == null)
+      throw new TypeError("Invalid attempt to iterate non-iterable instance.\\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method.");
+
+    var it, normalCompletion = true, didErr = false, err;
+
+    return {
+      s() {
+        it = o[Symbol.iterator]();
+      },
+      n() {
+        var step = it.next();
+        normalCompletion = step.done;
+        return step;
+      },
+      e(e) {
+        didErr = true;
+        err = e;
+      },
+      f() {
+        try {
+          if (!normalCompletion && it.return != null) it.return();
+        } finally {
+          if (didErr) throw err;
+        }
+      }
+    };
+  }
+`;
+
+helpers.createForOfIteratorHelperLoose = helper("7.9.0")`
+  export default function _createForOfIteratorHelperLoose(o) {
+    var i = 0;
+
+    if (typeof Symbol === "undefined" || o[Symbol.iterator] == null) {
+      if (Array.isArray(o))
+        return function() {
+          if (i >= o.length) return { done: true };
+          return { done: false, value: o[i++] };
+        }
+
+      throw new TypeError("Invalid attempt to iterate non-iterable instance.\\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method.");
+    }
+
+    i = o[Symbol.iterator]();
+    return i.next.bind(i);
+  }
+`;
+
 helpers.skipFirstGeneratorNext = helper("7.0.0-beta.0")`
   export default function _skipFirstGeneratorNext(fn) {
     return function () {

packages/babel-plugin-transform-block-scoping/test/fixtures/general/hoisting/options.json

@@ -4,6 +4,7 @@
     "syntax-jsx",
     "transform-react-jsx",
     "transform-block-scoped-functions",
-    "transform-for-of"
+    "transform-for-of",
+     ["external-helpers", { "helperVersion": "7.100.0" }]
   ]
 }

packages/babel-plugin-transform-block-scoping/test/fixtures/general/hoisting/output.js

@@ -10,12 +10,11 @@ var _loop = function (i) {
   });
 };
 
-var _iteratorNormalCompletion = true;
+var _iterator = babelHelpers.createForOfIteratorHelper(nums),
-var _didIteratorError = false;
+    _step;
-var _iteratorError = undefined;
 
 try {
-  for (var _iterator = nums[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
+  for (_iterator.s(); !(_step = _iterator.n()).done;) {
     var i = _step.value;
     var x;
     var f;
@@ -23,16 +22,7 @@ try {
     _loop(i);
   }
 } catch (err) {
-  _didIteratorError = true;
+  _iterator.e(err);
-  _iteratorError = err;
 } finally {
-  try {
+  _iterator.f();
-    if (!_iteratorNormalCompletion && _iterator.return != null) {
-      _iterator.return();
-    }
-  } finally {
-    if (_didIteratorError) {
-      throw _iteratorError;
-    }
-  }
 }

packages/babel-plugin-transform-for-of/src/index.js

@@ -1,6 +1,8 @@
 import { declare } from "@babel/helper-plugin-utils";
 import { template, types as t } from "@babel/core";
 
+import transformWithoutHelper from "./no-helper-implementation";
+
 export default declare((api, options) => {
   api.assertVersion(7);
 
@@ -79,56 +81,37 @@ export default declare((api, options) => {
     };
   }
 
-  const pushComputedProps = loose
-    ? pushComputedPropsLoose
-    : pushComputedPropsSpec;
-
   const buildForOfArray = template(`
     for (var KEY = 0, NAME = ARR; KEY < NAME.length; KEY++) BODY;
   `);
 
-  const buildForOfLoose = template(`
+  const buildForOfLoose = template.statements(`
-    for (var LOOP_OBJECT = OBJECT,
+    for (var ITERATOR_HELPER = CREATE_ITERATOR_HELPER(OBJECT), STEP_KEY;
-             IS_ARRAY = Array.isArray(LOOP_OBJECT),
+        !(STEP_KEY = ITERATOR_HELPER()).done;) BODY;
-             INDEX = 0,
+  `);
-             LOOP_OBJECT = IS_ARRAY ? LOOP_OBJECT : LOOP_OBJECT[Symbol.iterator]();;) {
+
-      INTERMEDIATE;
+  const buildForOf = template.statements(`
-      if (IS_ARRAY) {
+    var ITERATOR_HELPER = CREATE_ITERATOR_HELPER(OBJECT), STEP_KEY;
-        if (INDEX >= LOOP_OBJECT.length) break;
+    try {
-        ID = LOOP_OBJECT[INDEX++];
+      for (ITERATOR_HELPER.s(); !(STEP_KEY = ITERATOR_HELPER.n()).done;) BODY;
-      } else {
+    } catch (err) {
-        INDEX = LOOP_OBJECT.next();
+      ITERATOR_HELPER.e(err);
-        if (INDEX.done) break;
+    } finally {
-        ID = INDEX.value;
+      ITERATOR_HELPER.f();
-      }
     }
   `);
 
-  const buildForOf = template(`
+  const builder = loose
-    var ITERATOR_COMPLETION = true;
+    ? {
-    var ITERATOR_HAD_ERROR_KEY = false;
+        build: buildForOfLoose,
-    var ITERATOR_ERROR_KEY = undefined;
+        helper: "createForOfIteratorHelperLoose",
-    try {
+        getContainer: nodes => nodes,
-      for (
-        var ITERATOR_KEY = OBJECT[Symbol.iterator](), STEP_KEY;
-        !(ITERATOR_COMPLETION = (STEP_KEY = ITERATOR_KEY.next()).done);
-        ITERATOR_COMPLETION = true
-      ) {}
-    } catch (err) {
-      ITERATOR_HAD_ERROR_KEY = true;
-      ITERATOR_ERROR_KEY = err;
-    } finally {
-      try {
-        if (!ITERATOR_COMPLETION && ITERATOR_KEY.return != null) {
-          ITERATOR_KEY.return();
-        }
-      } finally {
-        if (ITERATOR_HAD_ERROR_KEY) {
-          throw ITERATOR_ERROR_KEY;
-        }
       }
-    }
+    : {
-  `);
+        build: buildForOf,
+        helper: "createForOfIteratorHelper",
+        getContainer: nodes => nodes[1].block.body,
+      };
 
   function _ForOfStatementArray(path) {
     const { node, scope } = path;
@@ -136,7 +119,7 @@ export default declare((api, options) => {
     const right = scope.generateUidIdentifierBasedOnNode(node.right, "arr");
     const iterationKey = scope.generateUidIdentifier("i");
 
-    let loop = buildForOfArray({
+    const loop = buildForOfArray({
       BODY: node.body,
       KEY: iterationKey,
       NAME: right,
@@ -164,19 +147,7 @@ export default declare((api, options) => {
       );
     }
 
-    if (path.parentPath.isLabeledStatement()) {
+    return loop;
-      loop = t.labeledStatement(path.parentPath.node.label, loop);
-    }
-
-    return [loop];
-  }
-
-  function replaceWithArray(path) {
-    if (path.parentPath.isLabeledStatement()) {
-      path.parentPath.replaceWithMultiple(_ForOfStatementArray(path));
-    } else {
-      path.replaceWithMultiple(_ForOfStatementArray(path));
-    }
   }
 
   return {
@@ -189,156 +160,64 @@ export default declare((api, options) => {
           right.isGenericType("Array") ||
           t.isArrayTypeAnnotation(right.getTypeAnnotation())
         ) {
-          replaceWithArray(path);
+          path.replaceWith(_ForOfStatementArray(path));
           return;
         }
 
-        const { node } = path;
+        if (!state.availableHelper(builder.helper)) {
-        const build = pushComputedProps(path, state);
+          // Babel <7.9.0 doesn't support this helper
-        const declar = build.declar;
+          transformWithoutHelper(loose, path, state);
-        const loop = build.loop;
+          return;
-        const block = loop.body;
+        }
+
+        const { node, parent, scope } = path;
+        const left = node.left;
+        let declar;
+
+        const stepKey = scope.generateUid("step");
+        const stepValue = t.memberExpression(
+          t.identifier(stepKey),
+          t.identifier("value"),
+        );
+
+        if (t.isVariableDeclaration(left)) {
+          // for (let i of test)
+          declar = t.variableDeclaration(left.kind, [
+            t.variableDeclarator(left.declarations[0].id, stepValue),
+          ]);
+        } else {
+          // for (i of test), for ({ i } of test)
+          declar = t.expressionStatement(
+            t.assignmentExpression("=", left, stepValue),
+          );
+        }
 
         // ensure that it's a block so we can take all its statements
         path.ensureBlock();
 
-        // add the value declaration to the new loop body
+        node.body.body.unshift(declar);
-        if (declar) {
-          block.body.push(declar);
-        }
 
-        // push the rest of the original loop body onto our new body
+        const nodes = builder.build({
-        block.body = block.body.concat(node.body.body);
+          CREATE_ITERATOR_HELPER: state.addHelper(builder.helper),
+          ITERATOR_HELPER: scope.generateUidIdentifier("iterator"),
+          STEP_KEY: t.identifier(stepKey),
+          OBJECT: node.right,
+          BODY: node.body,
+        });
+        const container = builder.getContainer(nodes);
 
-        t.inherits(loop, node);
+        t.inherits(container[0], node);
-        t.inherits(loop.body, node.body);
+        t.inherits(container[0].body, node.body);
 
-        if (build.replaceParent) {
+        if (t.isLabeledStatement(parent)) {
-          path.parentPath.replaceWithMultiple(build.node);
+          container[0] = t.labeledStatement(parent.label, container[0]);
+
+          path.parentPath.replaceWithMultiple(nodes);
           path.remove();
         } else {
-          path.replaceWithMultiple(build.node);
+          path.replaceWithMultiple(nodes);
         }
       },
     },
   };
-
-  function pushComputedPropsLoose(path, file) {
-    const { node, scope, parent } = path;
-    const { left } = node;
-    let declar, id, intermediate;
-
-    if (
-      t.isIdentifier(left) ||
-      t.isPattern(left) ||
-      t.isMemberExpression(left)
-    ) {
-      // for (i of test), for ({ i } of test)
-      id = left;
-      intermediate = null;
-    } else if (t.isVariableDeclaration(left)) {
-      // for (let i of test)
-      id = scope.generateUidIdentifier("ref");
-      declar = t.variableDeclaration(left.kind, [
-        t.variableDeclarator(left.declarations[0].id, t.identifier(id.name)),
-      ]);
-      intermediate = t.variableDeclaration("var", [
-        t.variableDeclarator(t.identifier(id.name)),
-      ]);
-    } else {
-      throw file.buildCodeFrameError(
-        left,
-        `Unknown node type ${left.type} in ForStatement`,
-      );
-    }
-
-    const iteratorKey = scope.generateUidIdentifier("iterator");
-    const isArrayKey = scope.generateUidIdentifier("isArray");
-
-    const loop = buildForOfLoose({
-      LOOP_OBJECT: iteratorKey,
-      IS_ARRAY: isArrayKey,
-      OBJECT: node.right,
-      INDEX: scope.generateUidIdentifier("i"),
-      ID: id,
-      INTERMEDIATE: intermediate,
-    });
-
-    //
-    const isLabeledParent = t.isLabeledStatement(parent);
-    let labeled;
-
-    if (isLabeledParent) {
-      labeled = t.labeledStatement(parent.label, loop);
-    }
-
-    return {
-      replaceParent: isLabeledParent,
-      declar: declar,
-      node: labeled || loop,
-      loop: loop,
-    };
-  }
-
-  function pushComputedPropsSpec(path, file) {
-    const { node, scope, parent } = path;
-    const left = node.left;
-    let declar;
-
-    const stepKey = scope.generateUid("step");
-    const stepValue = t.memberExpression(
-      t.identifier(stepKey),
-      t.identifier("value"),
-    );
-
-    if (
-      t.isIdentifier(left) ||
-      t.isPattern(left) ||
-      t.isMemberExpression(left)
-    ) {
-      // for (i of test), for ({ i } of test)
-      declar = t.expressionStatement(
-        t.assignmentExpression("=", left, stepValue),
-      );
-    } else if (t.isVariableDeclaration(left)) {
-      // for (let i of test)
-      declar = t.variableDeclaration(left.kind, [
-        t.variableDeclarator(left.declarations[0].id, stepValue),
-      ]);
-    } else {
-      throw file.buildCodeFrameError(
-        left,
-        `Unknown node type ${left.type} in ForStatement`,
-      );
-    }
-
-    const template = buildForOf({
-      ITERATOR_HAD_ERROR_KEY: scope.generateUidIdentifier("didIteratorError"),
-      ITERATOR_COMPLETION: scope.generateUidIdentifier(
-        "iteratorNormalCompletion",
-      ),
-      ITERATOR_ERROR_KEY: scope.generateUidIdentifier("iteratorError"),
-      ITERATOR_KEY: scope.generateUidIdentifier("iterator"),
-      STEP_KEY: t.identifier(stepKey),
-      OBJECT: node.right,
-    });
-
-    const isLabeledParent = t.isLabeledStatement(parent);
-
-    const tryBody = template[3].block.body;
-    const loop = tryBody[0];
-
-    if (isLabeledParent) {
-      tryBody[0] = t.labeledStatement(parent.label, loop);
-    }
-
-    //
-
-    return {
-      replaceParent: isLabeledParent,
-      declar: declar,
-      loop: loop,
-      node: template,
-    };
-  }
 });

packages/babel-plugin-transform-for-of/src/no-helper-implementation.js

@@ -0,0 +1,192 @@
+import { template, types as t } from "@babel/core";
+
+// This is the legacy implementation, which inlines all the code.
+// It must be kept for compatibility reasons.
+// TODO (Babel 8): Remove this code.
+
+export default function transformWithoutHelper(loose, path, state) {
+  const pushComputedProps = loose
+    ? pushComputedPropsLoose
+    : pushComputedPropsSpec;
+
+  const { node } = path;
+  const build = pushComputedProps(path, state);
+  const declar = build.declar;
+  const loop = build.loop;
+  const block = loop.body;
+
+  // ensure that it's a block so we can take all its statements
+  path.ensureBlock();
+
+  // add the value declaration to the new loop body
+  if (declar) {
+    block.body.push(declar);
+  }
+
+  // push the rest of the original loop body onto our new body
+  block.body = block.body.concat(node.body.body);
+
+  t.inherits(loop, node);
+  t.inherits(loop.body, node.body);
+
+  if (build.replaceParent) {
+    path.parentPath.replaceWithMultiple(build.node);
+    path.remove();
+  } else {
+    path.replaceWithMultiple(build.node);
+  }
+}
+
+const buildForOfLoose = template(`
+  for (var LOOP_OBJECT = OBJECT,
+          IS_ARRAY = Array.isArray(LOOP_OBJECT),
+          INDEX = 0,
+          LOOP_OBJECT = IS_ARRAY ? LOOP_OBJECT : LOOP_OBJECT[Symbol.iterator]();;) {
+    INTERMEDIATE;
+    if (IS_ARRAY) {
+      if (INDEX >= LOOP_OBJECT.length) break;
+      ID = LOOP_OBJECT[INDEX++];
+    } else {
+      INDEX = LOOP_OBJECT.next();
+      if (INDEX.done) break;
+      ID = INDEX.value;
+    }
+  }
+`);
+
+const buildForOf = template(`
+  var ITERATOR_COMPLETION = true;
+  var ITERATOR_HAD_ERROR_KEY = false;
+  var ITERATOR_ERROR_KEY = undefined;
+  try {
+    for (
+      var ITERATOR_KEY = OBJECT[Symbol.iterator](), STEP_KEY;
+      !(ITERATOR_COMPLETION = (STEP_KEY = ITERATOR_KEY.next()).done);
+      ITERATOR_COMPLETION = true
+    ) {}
+  } catch (err) {
+    ITERATOR_HAD_ERROR_KEY = true;
+    ITERATOR_ERROR_KEY = err;
+  } finally {
+    try {
+      if (!ITERATOR_COMPLETION && ITERATOR_KEY.return != null) {
+        ITERATOR_KEY.return();
+      }
+    } finally {
+      if (ITERATOR_HAD_ERROR_KEY) {
+        throw ITERATOR_ERROR_KEY;
+      }
+    }
+  }
+`);
+
+function pushComputedPropsLoose(path, file) {
+  const { node, scope, parent } = path;
+  const { left } = node;
+  let declar, id, intermediate;
+
+  if (t.isIdentifier(left) || t.isPattern(left) || t.isMemberExpression(left)) {
+    // for (i of test), for ({ i } of test)
+    id = left;
+    intermediate = null;
+  } else if (t.isVariableDeclaration(left)) {
+    // for (let i of test)
+    id = scope.generateUidIdentifier("ref");
+    declar = t.variableDeclaration(left.kind, [
+      t.variableDeclarator(left.declarations[0].id, t.identifier(id.name)),
+    ]);
+    intermediate = t.variableDeclaration("var", [
+      t.variableDeclarator(t.identifier(id.name)),
+    ]);
+  } else {
+    throw file.buildCodeFrameError(
+      left,
+      `Unknown node type ${left.type} in ForStatement`,
+    );
+  }
+
+  const iteratorKey = scope.generateUidIdentifier("iterator");
+  const isArrayKey = scope.generateUidIdentifier("isArray");
+
+  const loop = buildForOfLoose({
+    LOOP_OBJECT: iteratorKey,
+    IS_ARRAY: isArrayKey,
+    OBJECT: node.right,
+    INDEX: scope.generateUidIdentifier("i"),
+    ID: id,
+    INTERMEDIATE: intermediate,
+  });
+
+  //
+  const isLabeledParent = t.isLabeledStatement(parent);
+  let labeled;
+
+  if (isLabeledParent) {
+    labeled = t.labeledStatement(parent.label, loop);
+  }
+
+  return {
+    replaceParent: isLabeledParent,
+    declar: declar,
+    node: labeled || loop,
+    loop: loop,
+  };
+}
+
+function pushComputedPropsSpec(path, file) {
+  const { node, scope, parent } = path;
+  const left = node.left;
+  let declar;
+
+  const stepKey = scope.generateUid("step");
+  const stepValue = t.memberExpression(
+    t.identifier(stepKey),
+    t.identifier("value"),
+  );
+
+  if (t.isIdentifier(left) || t.isPattern(left) || t.isMemberExpression(left)) {
+    // for (i of test), for ({ i } of test)
+    declar = t.expressionStatement(
+      t.assignmentExpression("=", left, stepValue),
+    );
+  } else if (t.isVariableDeclaration(left)) {
+    // for (let i of test)
+    declar = t.variableDeclaration(left.kind, [
+      t.variableDeclarator(left.declarations[0].id, stepValue),
+    ]);
+  } else {
+    throw file.buildCodeFrameError(
+      left,
+      `Unknown node type ${left.type} in ForStatement`,
+    );
+  }
+
+  const template = buildForOf({
+    ITERATOR_HAD_ERROR_KEY: scope.generateUidIdentifier("didIteratorError"),
+    ITERATOR_COMPLETION: scope.generateUidIdentifier(
+      "iteratorNormalCompletion",
+    ),
+    ITERATOR_ERROR_KEY: scope.generateUidIdentifier("iteratorError"),
+    ITERATOR_KEY: scope.generateUidIdentifier("iterator"),
+    STEP_KEY: t.identifier(stepKey),
+    OBJECT: node.right,
+  });
+
+  const isLabeledParent = t.isLabeledStatement(parent);
+
+  const tryBody = template[3].block.body;
+  const loop = tryBody[0];
+
+  if (isLabeledParent) {
+    tryBody[0] = t.labeledStatement(parent.label, loop);
+  }
+
+  //
+
+  return {
+    replaceParent: isLabeledParent,
+    declar: declar,
+    loop: loop,
+    node: template,
+  };
+}

packages/babel-plugin-transform-for-of/test/fixtures/loose-exec/array-break.js

@@ -0,0 +1,9 @@
+let arr = (() => [1, 2, 3])(); // Disable inference
+let res = [];
+
+for (const x of arr) {
+  if (x === 2) break;
+  res.push(x);
+}
+
+expect(res).toEqual([1]);

packages/babel-plugin-transform-for-of/test/fixtures/loose-exec/array-continue.js

@@ -0,0 +1,9 @@
+let arr = (() => [1, 2, 3])(); // Disable inference
+let res = [];
+
+for (const x of arr) {
+  if (x === 2) continue;
+  res.push(x);
+}
+
+expect(res).toEqual([1, 3]);

packages/babel-plugin-transform-for-of/test/fixtures/loose-exec/array.js

@@ -0,0 +1,6 @@
+let arr = (() => [1, 2, 3])(); // Disable inference
+let res = [];
+
+for (const x of arr) res.push(x);
+
+expect(res).toEqual([1, 2, 3]);

packages/babel-plugin-transform-for-of/test/fixtures/loose-exec/generator-break.js

@@ -0,0 +1,12 @@
+function* f() {
+  yield 1; yield 2; yield 3;
+}
+
+let res = [];
+
+for (const x of f()) {
+  if (x === 2) break;
+  res.push(x);
+}
+
+expect(res).toEqual([1]);

packages/babel-plugin-transform-for-of/test/fixtures/loose-exec/generator-continue.js

@@ -0,0 +1,12 @@
+function* f() {
+  yield 1; yield 2; yield 3;
+}
+
+let res = [];
+
+for (const x of f()) {
+  if (x === 2) continue;
+  res.push(x);
+}
+
+expect(res).toEqual([1, 3]);

packages/babel-plugin-transform-for-of/test/fixtures/loose-exec/generator.js

@@ -0,0 +1,9 @@
+function* f() {
+  yield 1; yield 2; yield 3;
+}
+
+let res = [];
+
+for (const x of f()) res.push(x);
+
+expect(res).toEqual([1, 2, 3]);

packages/babel-plugin-transform-for-of/test/fixtures/loose-exec/options.json

@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["transform-for-of", { "loose": true }],
+    ["external-helpers", { "helperVersion": "7.100.0" }]
+  ]
+}

packages/babel-plugin-transform-for-of/test/fixtures/loose/identifier/output.js

@@ -1,10 +1,3 @@
-for (var _iterator = arr, _isArray = Array.isArray(_iterator), _i = 0, _iterator = _isArray ? _iterator : _iterator[Symbol.iterator]();;) {
+for (var _iterator = babelHelpers.createForOfIteratorHelperLoose(arr), _step; !(_step = _iterator()).done;) {
-  if (_isArray) {
+  i = _step.value;
-    if (_i >= _iterator.length) break;
-    i = _iterator[_i++];
-  } else {
-    _i = _iterator.next();
-    if (_i.done) break;
-    i = _i.value;
-  }
 }

packages/babel-plugin-transform-for-of/test/fixtures/loose/ignore-cases/output.js

@@ -1,16 +1,5 @@
-for (var _iterator = foo, _isArray = Array.isArray(_iterator), _i = 0, _iterator = _isArray ? _iterator : _iterator[Symbol.iterator]();;) {
+for (var _iterator = babelHelpers.createForOfIteratorHelperLoose(foo), _step; !(_step = _iterator()).done;) {
-  var _ref;
+  var i = _step.value;
-
-  if (_isArray) {
-    if (_i >= _iterator.length) break;
-    _ref = _iterator[_i++];
-  } else {
-    _i = _iterator.next();
-    if (_i.done) break;
-    _ref = _i.value;
-  }
-
-  var i = _ref;
 
   switch (i) {
     case 1:

packages/babel-plugin-transform-for-of/test/fixtures/loose/let/output.js

@@ -1,14 +1,3 @@
-for (var _iterator = arr, _isArray = Array.isArray(_iterator), _i = 0, _iterator = _isArray ? _iterator : _iterator[Symbol.iterator]();;) {
+for (var _iterator = babelHelpers.createForOfIteratorHelperLoose(arr), _step; !(_step = _iterator()).done;) {
-  var _ref;
+  let i = _step.value;
-
-  if (_isArray) {
-    if (_i >= _iterator.length) break;
-    _ref = _iterator[_i++];
-  } else {
-    _i = _iterator.next();
-    if (_i.done) break;
-    _ref = _i.value;
-  }
-
-  let i = _ref;
 }

packages/babel-plugin-transform-for-of/test/fixtures/loose/member-expression/output.js

@@ -1,10 +1,3 @@
-for (var _iterator = arr, _isArray = Array.isArray(_iterator), _i = 0, _iterator = _isArray ? _iterator : _iterator[Symbol.iterator]();;) {
+for (var _iterator = babelHelpers.createForOfIteratorHelperLoose(arr), _step; !(_step = _iterator()).done;) {
-  if (_isArray) {
+  obj.prop = _step.value;
-    if (_i >= _iterator.length) break;
-    obj.prop = _iterator[_i++];
-  } else {
-    _i = _iterator.next();
-    if (_i.done) break;
-    obj.prop = _i.value;
-  }
 }

packages/babel-plugin-transform-for-of/test/fixtures/loose/multiple/output.js

@@ -1,29 +1,7 @@
-for (var _iterator = arr, _isArray = Array.isArray(_iterator), _i = 0, _iterator = _isArray ? _iterator : _iterator[Symbol.iterator]();;) {
+for (var _iterator = babelHelpers.createForOfIteratorHelperLoose(arr), _step; !(_step = _iterator()).done;) {
-  var _ref;
+  var i = _step.value;
-
-  if (_isArray) {
-    if (_i >= _iterator.length) break;
-    _ref = _iterator[_i++];
-  } else {
-    _i = _iterator.next();
-    if (_i.done) break;
-    _ref = _i.value;
-  }
-
-  var i = _ref;
 }
 
-for (var _iterator2 = numbers, _isArray2 = Array.isArray(_iterator2), _i2 = 0, _iterator2 = _isArray2 ? _iterator2 : _iterator2[Symbol.iterator]();;) {
+for (var _iterator2 = babelHelpers.createForOfIteratorHelperLoose(numbers), _step2; !(_step2 = _iterator2()).done;) {
-  var _ref2;
+  var i = _step2.value;
-
-  if (_isArray2) {
-    if (_i2 >= _iterator2.length) break;
-    _ref2 = _iterator2[_i2++];
-  } else {
-    _i2 = _iterator2.next();
-    if (_i2.done) break;
-    _ref2 = _i2.value;
-  }
-
-  var i = _ref2;
 }

packages/babel-plugin-transform-for-of/test/fixtures/loose/nested-label-for-of/output.js

@@ -1,30 +1,8 @@
-b: for (var _iterator = d(), _isArray = Array.isArray(_iterator), _i = 0, _iterator = _isArray ? _iterator : _iterator[Symbol.iterator]();;) {
+b: for (var _iterator = babelHelpers.createForOfIteratorHelperLoose(d()), _step; !(_step = _iterator()).done;) {
-  var _ref;
+  let c = _step.value;
 
-  if (_isArray) {
+  for (var _iterator2 = babelHelpers.createForOfIteratorHelperLoose(f()), _step2; !(_step2 = _iterator2()).done;) {
-    if (_i >= _iterator.length) break;
+    let e = _step2.value;
-    _ref = _iterator[_i++];
-  } else {
-    _i = _iterator.next();
-    if (_i.done) break;
-    _ref = _i.value;
-  }
-
-  let c = _ref;
-
-  for (var _iterator2 = f(), _isArray2 = Array.isArray(_iterator2), _i2 = 0, _iterator2 = _isArray2 ? _iterator2 : _iterator2[Symbol.iterator]();;) {
-    var _ref2;
-
-    if (_isArray2) {
-      if (_i2 >= _iterator2.length) break;
-      _ref2 = _iterator2[_i2++];
-    } else {
-      _i2 = _iterator2.next();
-      if (_i2.done) break;
-      _ref2 = _i2.value;
-    }
-
-    let e = _ref2;
     continue b;
   }
 }

packages/babel-plugin-transform-for-of/test/fixtures/loose/options.json

@@ -1,3 +1,6 @@
 {
-  "plugins": [["transform-for-of", { "loose": true }]]
+  "plugins": [
+    ["transform-for-of", { "loose": true }],
+    ["external-helpers", { "helperVersion": "7.100.0" }]
+  ]
 }

packages/babel-plugin-transform-for-of/test/fixtures/loose/var/output.js

@@ -1,14 +1,3 @@
-for (var _iterator = arr, _isArray = Array.isArray(_iterator), _i = 0, _iterator = _isArray ? _iterator : _iterator[Symbol.iterator]();;) {
+for (var _iterator = babelHelpers.createForOfIteratorHelperLoose(arr), _step; !(_step = _iterator()).done;) {
-  var _ref;
+  var i = _step.value;
-
-  if (_isArray) {
-    if (_i >= _iterator.length) break;
-    _ref = _iterator[_i++];
-  } else {
-    _i = _iterator.next();
-    if (_i.done) break;
-    _ref = _i.value;
-  }
-
-  var i = _ref;
 }

packages/babel-plugin-transform-for-of/test/fixtures/opt/options.json

@@ -1,3 +1,7 @@
 {
-  "plugins": ["transform-for-of", "transform-flow-strip-types"]
+  "plugins": [
+    "transform-for-of",
+    "transform-flow-strip-types",
+     ["external-helpers", { "helperVersion": "7.100.0" }]
+  ]
 }

packages/babel-plugin-transform-for-of/test/fixtures/opt/typeannotation/output.js

@@ -3,26 +3,16 @@ for (var _i = 0, _arr = b; _i < _arr.length; _i++) {
 }
 
 function a(b) {
-  var _iteratorNormalCompletion = true;
+  var _iterator = babelHelpers.createForOfIteratorHelper(b),
-  var _didIteratorError = false;
+      _step;
-  var _iteratorError = undefined;
 
   try {
-    for (var _iterator = b[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
+    for (_iterator.s(); !(_step = _iterator.n()).done;) {
       const y = _step.value;
     }
   } catch (err) {
-    _didIteratorError = true;
+    _iterator.e(err);
-    _iteratorError = err;
   } finally {
-    try {
+    _iterator.f();
-      if (!_iteratorNormalCompletion && _iterator.return != null) {
-        _iterator.return();
-      }
-    } finally {
-      if (_didIteratorError) {
-        throw _iteratorError;
-      }
-    }
   }
 }

packages/babel-plugin-transform-for-of/test/fixtures/regression/if-label-3858/output.js

@@ -1,5 +1,3 @@
-if (true) {
+if (true) loop: for (var _i = 0, _arr = []; _i < _arr.length; _i++) {
-  loop: for (var _i = 0, _arr = []; _i < _arr.length; _i++) {
+  let ch = _arr[_i];
-    let ch = _arr[_i];
-  }
 }

packages/babel-plugin-transform-for-of/test/fixtures/regression/label-object-with-comment-4995/output.js

@@ -1,24 +1,14 @@
-var _iteratorNormalCompletion = true;
+var _iterator = babelHelpers.createForOfIteratorHelper(b),
-var _didIteratorError = false;
+    _step;
-var _iteratorError = undefined;
 
 try {
   myLabel: //woops
-  for (var _iterator = b[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
+  for (_iterator.s(); !(_step = _iterator.n()).done;) {
     let a = _step.value;
     continue myLabel;
   }
 } catch (err) {
-  _didIteratorError = true;
+  _iterator.e(err);
-  _iteratorError = err;
 } finally {
-  try {
+  _iterator.f();
-    if (!_iteratorNormalCompletion && _iterator.return != null) {
-      _iterator.return();
-    }
-  } finally {
-    if (_didIteratorError) {
-      throw _iteratorError;
-    }
-  }
 }

packages/babel-plugin-transform-for-of/test/fixtures/regression/options.json

@@ -1,3 +1,6 @@
 {
-  "plugins": ["transform-for-of"]
+  "plugins": [
+    "transform-for-of",
+    ["external-helpers", { "helperVersion": "7.100.0" }]
+  ]
 }

packages/babel-plugin-transform-for-of/test/fixtures/spec-exec/array-break.js

@@ -0,0 +1,9 @@
+let arr = (() => [1, 2, 3])(); // Disable inference
+let res = [];
+
+for (const x of arr) {
+  if (x === 2) break;
+  res.push(x);
+}
+
+expect(res).toEqual([1]);

packages/babel-plugin-transform-for-of/test/fixtures/spec-exec/array-continue.js

@@ -0,0 +1,9 @@
+let arr = (() => [1, 2, 3])(); // Disable inference
+let res = [];
+
+for (const x of arr) {
+  if (x === 2) continue;
+  res.push(x);
+}
+
+expect(res).toEqual([1, 3]);

packages/babel-plugin-transform-for-of/test/fixtures/spec-exec/array.js

@@ -0,0 +1,6 @@
+let arr = (() => [1, 2, 3])(); // Disable inference
+let res = [];
+
+for (const x of arr) res.push(x);
+
+expect(res).toEqual([1, 2, 3]);

packages/babel-plugin-transform-for-of/test/fixtures/spec-exec/generator-break.js

@@ -0,0 +1,12 @@
+function* f() {
+  yield 1; yield 2; yield 3;
+}
+
+let res = [];
+
+for (const x of f()) {
+  if (x === 2) break;
+  res.push(x);
+}
+
+expect(res).toEqual([1]);

packages/babel-plugin-transform-for-of/test/fixtures/spec-exec/generator-continue.js

@@ -0,0 +1,12 @@
+function* f() {
+  yield 1; yield 2; yield 3;
+}
+
+let res = [];
+
+for (const x of f()) {
+  if (x === 2) continue;
+  res.push(x);
+}
+
+expect(res).toEqual([1, 3]);

packages/babel-plugin-transform-for-of/test/fixtures/spec-exec/generator.js

@@ -0,0 +1,9 @@
+function* f() {
+  yield 1; yield 2; yield 3;
+}
+
+let res = [];
+
+for (const x of f()) res.push(x);
+
+expect(res).toEqual([1, 2, 3]);

packages/babel-plugin-transform-for-of/test/fixtures/spec-exec/options.json

@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["transform-for-of", { "loose": false }],
+    ["external-helpers", { "helperVersion": "7.100.0" }]
+  ]
+}

packages/babel-plugin-transform-for-of/test/fixtures/spec-exec/throw-iterator-handling.js

@@ -0,0 +1,35 @@
+let done = false, value = 0;
+
+// jest.fn isn't available in exec tests
+function fn(impl = () => {}) {
+  function f() {
+    f.calls++;
+    return impl();
+  }
+  f.calls = 0;
+  return f;
+}
+
+const iterator = {
+  next: fn(() => ({ done, value })),
+  throw: fn(),
+  return: fn(() => { throw {} }),
+};
+
+const obj = {
+  [Symbol.iterator]: fn(() => iterator),
+};
+
+const err = new Error();
+
+expect(() => {
+  for (const x of obj) {
+    value++;
+    if (value == 2) throw err;
+  }
+}).toThrow(err);
+
+expect(obj[Symbol.iterator].calls).toBe(1);
+expect(iterator.next.calls).toBe(2);
+expect(iterator.throw.calls).toBe(0);
+expect(iterator.return.calls).toBe(1);

packages/babel-plugin-transform-for-of/test/fixtures/spec/identifier/output.js

@@ -1,22 +1,12 @@
-var _iteratorNormalCompletion = true;
+var _iterator = babelHelpers.createForOfIteratorHelper(arr),
-var _didIteratorError = false;
+    _step;
-var _iteratorError = undefined;
 
 try {
-  for (var _iterator = arr[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
+  for (_iterator.s(); !(_step = _iterator.n()).done;) {
     i = _step.value;
   }
 } catch (err) {
-  _didIteratorError = true;
+  _iterator.e(err);
-  _iteratorError = err;
 } finally {
-  try {
+  _iterator.f();
-    if (!_iteratorNormalCompletion && _iterator.return != null) {
-      _iterator.return();
-    }
-  } finally {
-    if (_didIteratorError) {
-      throw _iteratorError;
-    }
-  }
 }

packages/babel-plugin-transform-for-of/test/fixtures/spec/ignore-cases/output.js

@@ -1,9 +1,8 @@
-var _iteratorNormalCompletion = true;
+var _iterator = babelHelpers.createForOfIteratorHelper(foo),
-var _didIteratorError = false;
+    _step;
-var _iteratorError = undefined;
 
 try {
-  for (var _iterator = foo[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
+  for (_iterator.s(); !(_step = _iterator.n()).done;) {
     var i = _step.value;
 
     switch (i) {
@@ -12,16 +11,7 @@ try {
     }
   }
 } catch (err) {
-  _didIteratorError = true;
+  _iterator.e(err);
-  _iteratorError = err;
 } finally {
-  try {
+  _iterator.f();
-    if (!_iteratorNormalCompletion && _iterator.return != null) {
-      _iterator.return();
-    }
-  } finally {
-    if (_didIteratorError) {
-      throw _iteratorError;
-    }
-  }
 }

packages/babel-plugin-transform-for-of/test/fixtures/spec/let/output.js

@@ -1,22 +1,12 @@
-var _iteratorNormalCompletion = true;
+var _iterator = babelHelpers.createForOfIteratorHelper(arr),
-var _didIteratorError = false;
+    _step;
-var _iteratorError = undefined;
 
 try {
-  for (var _iterator = arr[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
+  for (_iterator.s(); !(_step = _iterator.n()).done;) {
     let i = _step.value;
   }
 } catch (err) {
-  _didIteratorError = true;
+  _iterator.e(err);
-  _iteratorError = err;
 } finally {
-  try {
+  _iterator.f();
-    if (!_iteratorNormalCompletion && _iterator.return != null) {
-      _iterator.return();
-    }
-  } finally {
-    if (_didIteratorError) {
-      throw _iteratorError;
-    }
-  }
 }

packages/babel-plugin-transform-for-of/test/fixtures/spec/member-expression/output.js

@@ -1,22 +1,12 @@
-var _iteratorNormalCompletion = true;
+var _iterator = babelHelpers.createForOfIteratorHelper(arr),
-var _didIteratorError = false;
+    _step;
-var _iteratorError = undefined;
 
 try {
-  for (var _iterator = arr[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
+  for (_iterator.s(); !(_step = _iterator.n()).done;) {
     obj.prop = _step.value;
   }
 } catch (err) {
-  _didIteratorError = true;
+  _iterator.e(err);
-  _iteratorError = err;
 } finally {
-  try {
+  _iterator.f();
-    if (!_iteratorNormalCompletion && _iterator.return != null) {
-      _iterator.return();
-    }
-  } finally {
-    if (_didIteratorError) {
-      throw _iteratorError;
-    }
-  }
 }

packages/babel-plugin-transform-for-of/test/fixtures/spec/multiple/output.js

@@ -1,45 +1,25 @@
-var _iteratorNormalCompletion = true;
+var _iterator = babelHelpers.createForOfIteratorHelper(arr),
-var _didIteratorError = false;
+    _step;
-var _iteratorError = undefined;
 
 try {
-  for (var _iterator = arr[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
+  for (_iterator.s(); !(_step = _iterator.n()).done;) {
     var i = _step.value;
   }
 } catch (err) {
-  _didIteratorError = true;
+  _iterator.e(err);
-  _iteratorError = err;
 } finally {
-  try {
+  _iterator.f();
-    if (!_iteratorNormalCompletion && _iterator.return != null) {
-      _iterator.return();
-    }
-  } finally {
-    if (_didIteratorError) {
-      throw _iteratorError;
-    }
-  }
 }
 
-var _iteratorNormalCompletion2 = true;
+var _iterator2 = babelHelpers.createForOfIteratorHelper(numbers),
-var _didIteratorError2 = false;
+    _step2;
-var _iteratorError2 = undefined;
 
 try {
-  for (var _iterator2 = numbers[Symbol.iterator](), _step2; !(_iteratorNormalCompletion2 = (_step2 = _iterator2.next()).done); _iteratorNormalCompletion2 = true) {
+  for (_iterator2.s(); !(_step2 = _iterator2.n()).done;) {
     var i = _step2.value;
   }
 } catch (err) {
-  _didIteratorError2 = true;
+  _iterator2.e(err);
-  _iteratorError2 = err;
 } finally {
-  try {
+  _iterator2.f();
-    if (!_iteratorNormalCompletion2 && _iterator2.return != null) {
-      _iterator2.return();
-    }
-  } finally {
-    if (_didIteratorError2) {
-      throw _iteratorError2;
-    }
-  }
 }

packages/babel-plugin-transform-for-of/test/fixtures/spec/nested-label-for-of/output.js

@@ -1,45 +1,26 @@
-var _iteratorNormalCompletion = true;
+var _iterator = babelHelpers.createForOfIteratorHelper(d()),
-var _didIteratorError = false;
+    _step;
-var _iteratorError = undefined;
 
 try {
-  b: for (var _iterator = d()[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
+  b: for (_iterator.s(); !(_step = _iterator.n()).done;) {
     let c = _step.value;
-    var _iteratorNormalCompletion2 = true;
+
-    var _didIteratorError2 = false;
+    var _iterator2 = babelHelpers.createForOfIteratorHelper(f()),
-    var _iteratorError2 = undefined;
+        _step2;
 
     try {
-      for (var _iterator2 = f()[Symbol.iterator](), _step2; !(_iteratorNormalCompletion2 = (_step2 = _iterator2.next()).done); _iteratorNormalCompletion2 = true) {
+      for (_iterator2.s(); !(_step2 = _iterator2.n()).done;) {
         let e = _step2.value;
         continue b;
       }
     } catch (err) {
-      _didIteratorError2 = true;
+      _iterator2.e(err);
-      _iteratorError2 = err;
     } finally {
-      try {
+      _iterator2.f();
-        if (!_iteratorNormalCompletion2 && _iterator2.return != null) {
-          _iterator2.return();
-        }
-      } finally {
-        if (_didIteratorError2) {
-          throw _iteratorError2;
-        }
-      }
     }
   }
 } catch (err) {
-  _didIteratorError = true;
+  _iterator.e(err);
-  _iteratorError = err;
 } finally {
-  try {
+  _iterator.f();
-    if (!_iteratorNormalCompletion && _iterator.return != null) {
-      _iterator.return();
-    }
-  } finally {
-    if (_didIteratorError) {
-      throw _iteratorError;
-    }
-  }
 }

packages/babel-plugin-transform-for-of/test/fixtures/spec/options.json

@@ -1,3 +1,6 @@
 {
-  "plugins": ["transform-for-of"]
+  "plugins": [
+    "transform-for-of",
+     ["external-helpers", { "helperVersion": "7.100.0" }]
+  ]
 }

packages/babel-plugin-transform-for-of/test/fixtures/spec/var/output.js

@@ -1,22 +1,12 @@
-var _iteratorNormalCompletion = true;
+var _iterator = babelHelpers.createForOfIteratorHelper(arr),
-var _didIteratorError = false;
+    _step;
-var _iteratorError = undefined;
 
 try {
-  for (var _iterator = arr[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
+  for (_iterator.s(); !(_step = _iterator.n()).done;) {
     var i = _step.value;
   }
 } catch (err) {
-  _didIteratorError = true;
+  _iterator.e(err);
-  _iteratorError = err;
 } finally {
-  try {
+  _iterator.f();
-    if (!_iteratorNormalCompletion && _iterator.return != null) {
-      _iterator.return();
-    }
-  } finally {
-    if (_didIteratorError) {
-      throw _iteratorError;
-    }
-  }
 }

packages/babel-plugin-transform-parameters/test/fixtures/parameters/options.json

@@ -1,7 +1,7 @@
 {
   "plugins": [
     "proposal-class-properties",
-    "external-helpers",
+     ["external-helpers", { "helperVersion": "7.100.0" }],
     "syntax-typescript",
     "syntax-flow",
     "transform-parameters",

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

@@ -153,28 +153,18 @@ function forOf() {
     rest[_key16] = arguments[_key16];
   }
 
-  var _iteratorNormalCompletion = true;
+  var _iterator = babelHelpers.createForOfIteratorHelper(this),
-  var _didIteratorError = false;
+      _step;
-  var _iteratorError = undefined;
 
   try {
-    for (var _iterator = this[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
+    for (_iterator.s(); !(_step = _iterator.n()).done;) {
       rest[0] = _step.value;
       ;
     }
   } catch (err) {
-    _didIteratorError = true;
+    _iterator.e(err);
-    _iteratorError = err;
   } finally {
-    try {
+    _iterator.f();
-      if (!_iteratorNormalCompletion && _iterator.return != null) {
-        _iterator.return();
-      }
-    } finally {
-      if (_didIteratorError) {
-        throw _iteratorError;
-      }
-    }
   }
 }
 

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

@@ -1,7 +1,3 @@
-function _createSuper(Derived) { return function () { var Super = babelHelpers.getPrototypeOf(Derived), result; if (_isNativeReflectConstruct()) { var NewTarget = babelHelpers.getPrototypeOf(this).constructor; result = Reflect.construct(Super, arguments, NewTarget); } else { result = Super.apply(this, arguments); } return babelHelpers.possibleConstructorReturn(this, result); }; }
-
-function _isNativeReflectConstruct() { if (typeof Reflect === "undefined" || !Reflect.construct) return false; if (Reflect.construct.sham) return false; if (typeof Proxy === "function") return true; try { Date.prototype.toString.call(Reflect.construct(Date, [], function () {})); return true; } catch (e) { return false; } }
-
 function broken(x) {
   if (true) {
     var Foo = /*#__PURE__*/function (_Bar) {
@@ -9,7 +5,7 @@ function broken(x) {
 
       babelHelpers.inherits(Foo, _Bar);
 
-      var _super = _createSuper(Foo);
+      var _super = babelHelpers.createSuper(Foo);
 
       function Foo() {
         babelHelpers.classCallCheck(this, Foo);

packages/babel-plugin-transform-runtime/test/fixtures/runtime-corejs2/es6-for-of/options.json

@@ -1,3 +1,6 @@
 {
-  "plugins": ["transform-for-of", ["transform-runtime", { "corejs": 2 }]]
+  "plugins": [
+    "transform-for-of",
+    ["transform-runtime", { "corejs": 2, "version": "7.100.0" }]
+  ]
 }

packages/babel-plugin-transform-runtime/test/fixtures/runtime-corejs2/es6-for-of/output.js

@@ -1,24 +1,14 @@
-var _getIterator = require("@babel/runtime-corejs2/core-js/get-iterator");
+var _createForOfIteratorHelper = require("@babel/runtime-corejs2/helpers/createForOfIteratorHelper");
 
-var _iteratorNormalCompletion = true;
+var _iterator = _createForOfIteratorHelper(arr),
-var _didIteratorError = false;
+    _step;
-var _iteratorError = undefined;
 
 try {
-  for (var _iterator = _getIterator(arr), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
+  for (_iterator.s(); !(_step = _iterator.n()).done;) {
     var i = _step.value;
   }
 } catch (err) {
-  _didIteratorError = true;
+  _iterator.e(err);
-  _iteratorError = err;
 } finally {
-  try {
+  _iterator.f();
-    if (!_iteratorNormalCompletion && _iterator.return != null) {
-      _iterator.return();
-    }
-  } finally {
-    if (_didIteratorError) {
-      throw _iteratorError;
-    }
-  }
 }

packages/babel-plugin-transform-runtime/test/fixtures/runtime-corejs3/es6-for-of/options.json

@@ -1,3 +1,6 @@
 {
-  "plugins": ["transform-for-of", ["transform-runtime", { "corejs": 3 }]]
+  "plugins": [
+    "transform-for-of",
+    ["transform-runtime", { "corejs": 3, "version": "7.100.0" }]
+  ]
 }

packages/babel-plugin-transform-runtime/test/fixtures/runtime-corejs3/es6-for-of/output.js

@@ -1,24 +1,14 @@
-var _getIterator = require("@babel/runtime-corejs3/core-js/get-iterator");
+var _createForOfIteratorHelper = require("@babel/runtime-corejs3/helpers/createForOfIteratorHelper");
 
-var _iteratorNormalCompletion = true;
+var _iterator = _createForOfIteratorHelper(arr),
-var _didIteratorError = false;
+    _step;
-var _iteratorError = undefined;
 
 try {
-  for (var _iterator = _getIterator(arr), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
+  for (_iterator.s(); !(_step = _iterator.n()).done;) {
     var i = _step.value;
   }
 } catch (err) {
-  _didIteratorError = true;
+  _iterator.e(err);
-  _iteratorError = err;
 } finally {
-  try {
+  _iterator.f();
-    if (!_iteratorNormalCompletion && _iterator.return != null) {
-      _iterator.return();
-    }
-  } finally {
-    if (_didIteratorError) {
-      throw _iteratorError;
-    }
-  }
 }

packages/babel-plugin-transform-runtime/test/fixtures/runtime/es6-for-of/options.json

@@ -1,3 +1,6 @@
 {
-  "plugins": ["transform-for-of", "transform-runtime"]
+  "plugins": [
+    "transform-for-of",
+    ["transform-runtime", { "version": "7.100.0" }]
+  ]
 }

packages/babel-plugin-transform-runtime/test/fixtures/runtime/es6-for-of/output.js

@@ -1,22 +1,14 @@
-var _iteratorNormalCompletion = true;
+var _createForOfIteratorHelper = require("@babel/runtime/helpers/createForOfIteratorHelper");
-var _didIteratorError = false;
+
-var _iteratorError = undefined;
+var _iterator = _createForOfIteratorHelper(arr),
+    _step;
 
 try {
-  for (var _iterator = arr[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
+  for (_iterator.s(); !(_step = _iterator.n()).done;) {
     var i = _step.value;
   }
 } catch (err) {
-  _didIteratorError = true;
+  _iterator.e(err);
-  _iteratorError = err;
 } finally {
-  try {
+  _iterator.f();
-    if (!_iteratorNormalCompletion && _iterator.return != null) {
-      _iterator.return();
-    }
-  } finally {
-    if (_didIteratorError) {
-      throw _iteratorError;
-    }
-  }
 }

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

@@ -6,10 +6,11 @@ function _iterableToArrayLimit(arr, i) { if ((typeof Symbol === "undefined" || !
 
 function _arrayWithHoles(arr) { if (Array.isArray(arr)) return arr; }
 
+function _createForOfIteratorHelper(o) { if (typeof Symbol === "undefined" || o[Symbol.iterator] == null) throw new TypeError("Invalid attempt to iterate non-iterable instance.\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method."); var it, normalCompletion = true, didErr = false, err; return { s: function s() { it = o[Symbol.iterator](); }, n: function n() { var step = it.next(); normalCompletion = step.done; return step; }, e: function e(_e) { didErr = true; err = _e; }, f: function f() { try { if (!normalCompletion && it["return"] != null) it["return"](); } finally { if (didErr) throw err; } } }; }
+
 // https://github.com/babel/babel/issues/7557
-var _iteratorNormalCompletion = true;
+var _iterator = _createForOfIteratorHelper(c),
-var _didIteratorError = false;
+    _step;
-var _iteratorError = undefined;
 
 try {
   var _loop = function _loop() {
@@ -23,20 +24,11 @@ try {
     });
   };
 
-  for (var _iterator = c[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
+  for (_iterator.s(); !(_step = _iterator.n()).done;) {
     _loop();
   }
 } catch (err) {
-  _didIteratorError = true;
+  _iterator.e(err);
-  _iteratorError = err;
 } finally {
-  try {
+  _iterator.f();
-    if (!_iteratorNormalCompletion && _iterator["return"] != null) {
-      _iterator["return"]();
-    }
-  } finally {
-    if (_didIteratorError) {
-      throw _iteratorError;
-    }
-  }
 }