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node_modules/core-js/internals/iterator-map.js

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+'use strict';
+var call = require('../internals/function-call');
+var aCallable = require('../internals/a-callable');
+var anObject = require('../internals/an-object');
+var getIteratorDirect = require('../internals/get-iterator-direct');
+var createIteratorProxy = require('../internals/iterator-create-proxy');
+var callWithSafeIterationClosing = require('../internals/call-with-safe-iteration-closing');
+
+var IteratorProxy = createIteratorProxy(function () {
+  var iterator = this.iterator;
+  var result = anObject(call(this.next, iterator));
+  var done = this.done = !!result.done;
+  if (!done) return callWithSafeIterationClosing(iterator, this.mapper, [result.value, this.counter++], true);
+});
+
+// `Iterator.prototype.map` method
+// https://github.com/tc39/proposal-iterator-helpers
+module.exports = function map(mapper) {
+  anObject(this);
+  aCallable(mapper);
+  return new IteratorProxy(getIteratorDirect(this), {
+    mapper: mapper
+  });
+};