'use strict'; 
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var globalThis = require('../internals/global-this'); 
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var NativePromiseConstructor = require('../internals/promise-native-constructor'); 
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var isCallable = require('../internals/is-callable'); 
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var isForced = require('../internals/is-forced'); 
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var inspectSource = require('../internals/inspect-source'); 
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var wellKnownSymbol = require('../internals/well-known-symbol'); 
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var ENVIRONMENT = require('../internals/environment'); 
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var IS_PURE = require('../internals/is-pure'); 
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var V8_VERSION = require('../internals/environment-v8-version'); 
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var NativePromisePrototype = NativePromiseConstructor && NativePromiseConstructor.prototype; 
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var SPECIES = wellKnownSymbol('species'); 
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var SUBCLASSING = false; 
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var NATIVE_PROMISE_REJECTION_EVENT = isCallable(globalThis.PromiseRejectionEvent); 
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var FORCED_PROMISE_CONSTRUCTOR = isForced('Promise', function () { 
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  var PROMISE_CONSTRUCTOR_SOURCE = inspectSource(NativePromiseConstructor); 
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  var GLOBAL_CORE_JS_PROMISE = PROMISE_CONSTRUCTOR_SOURCE !== String(NativePromiseConstructor); 
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  // V8 6.6 (Node 10 and Chrome 66) have a bug with resolving custom thenables 
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  // https://bugs.chromium.org/p/chromium/issues/detail?id=830565 
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  // We can't detect it synchronously, so just check versions 
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  if (!GLOBAL_CORE_JS_PROMISE && V8_VERSION === 66) return true; 
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  // We need Promise#{ catch, finally } in the pure version for preventing prototype pollution 
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  if (IS_PURE && !(NativePromisePrototype['catch'] && NativePromisePrototype['finally'])) return true; 
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  // We can't use @@species feature detection in V8 since it causes 
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  // deoptimization and performance degradation 
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  // https://github.com/zloirock/core-js/issues/679 
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  if (!V8_VERSION || V8_VERSION < 51 || !/native code/.test(PROMISE_CONSTRUCTOR_SOURCE)) { 
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    // Detect correctness of subclassing with @@species support 
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    var promise = new NativePromiseConstructor(function (resolve) { resolve(1); }); 
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    var FakePromise = function (exec) { 
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      exec(function () { /* empty */ }, function () { /* empty */ }); 
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    }; 
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    var constructor = promise.constructor = {}; 
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    constructor[SPECIES] = FakePromise; 
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    SUBCLASSING = promise.then(function () { /* empty */ }) instanceof FakePromise; 
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    if (!SUBCLASSING) return true; 
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  // Unhandled rejections tracking support, NodeJS Promise without it fails @@species test 
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  } return !GLOBAL_CORE_JS_PROMISE && (ENVIRONMENT === 'BROWSER' || ENVIRONMENT === 'DENO') && !NATIVE_PROMISE_REJECTION_EVENT; 
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}); 
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module.exports = { 
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  CONSTRUCTOR: FORCED_PROMISE_CONSTRUCTOR, 
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  REJECTION_EVENT: NATIVE_PROMISE_REJECTION_EVENT, 
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  SUBCLASSING: SUBCLASSING 
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}; 
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