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node_modules/core-js/internals/iterator-create-proxy.js

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+'use strict';
+var call = require('../internals/function-call');
+var create = require('../internals/object-create');
+var createNonEnumerableProperty = require('../internals/create-non-enumerable-property');
+var defineBuiltIns = require('../internals/define-built-ins');
+var wellKnownSymbol = require('../internals/well-known-symbol');
+var InternalStateModule = require('../internals/internal-state');
+var getMethod = require('../internals/get-method');
+var IteratorPrototype = require('../internals/iterators-core').IteratorPrototype;
+var createIterResultObject = require('../internals/create-iter-result-object');
+var iteratorClose = require('../internals/iterator-close');
+
+var TO_STRING_TAG = wellKnownSymbol('toStringTag');
+var ITERATOR_HELPER = 'IteratorHelper';
+var WRAP_FOR_VALID_ITERATOR = 'WrapForValidIterator';
+var setInternalState = InternalStateModule.set;
+
+var createIteratorProxyPrototype = function (IS_ITERATOR) {
+  var getInternalState = InternalStateModule.getterFor(IS_ITERATOR ? WRAP_FOR_VALID_ITERATOR : ITERATOR_HELPER);
+
+  return defineBuiltIns(create(IteratorPrototype), {
+    next: function next() {
+      var state = getInternalState(this);
+      // for simplification:
+      //   for `%WrapForValidIteratorPrototype%.next` our `nextHandler` returns `IterResultObject`
+      //   for `%IteratorHelperPrototype%.next` - just a value
+      if (IS_ITERATOR) return state.nextHandler();
+      try {
+        var result = state.done ? undefined : state.nextHandler();
+        return createIterResultObject(result, state.done);
+      } catch (error) {
+        state.done = true;
+        throw error;
+      }
+    },
+    'return': function () {
+      var state = getInternalState(this);
+      var iterator = state.iterator;
+      state.done = true;
+      if (IS_ITERATOR) {
+        var returnMethod = getMethod(iterator, 'return');
+        return returnMethod ? call(returnMethod, iterator) : createIterResultObject(undefined, true);
+      }
+      if (state.inner) try {
+        iteratorClose(state.inner.iterator, 'normal');
+      } catch (error) {
+        return iteratorClose(iterator, 'throw', error);
+      }
+      iteratorClose(iterator, 'normal');
+      return createIterResultObject(undefined, true);
+    }
+  });
+};
+
+var WrapForValidIteratorPrototype = createIteratorProxyPrototype(true);
+var IteratorHelperPrototype = createIteratorProxyPrototype(false);
+
+createNonEnumerableProperty(IteratorHelperPrototype, TO_STRING_TAG, 'Iterator Helper');
+
+module.exports = function (nextHandler, IS_ITERATOR) {
+  var IteratorProxy = function Iterator(record, state) {
+    if (state) {
+      state.iterator = record.iterator;
+      state.next = record.next;
+    } else state = record;
+    state.type = IS_ITERATOR ? WRAP_FOR_VALID_ITERATOR : ITERATOR_HELPER;
+    state.nextHandler = nextHandler;
+    state.counter = 0;
+    state.done = false;
+    setInternalState(this, state);
+  };
+
+  IteratorProxy.prototype = IS_ITERATOR ? WrapForValidIteratorPrototype : IteratorHelperPrototype;
+
+  return IteratorProxy;
+};