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Editing: array-method-has-species-support.js
var fails = require('../internals/fails'); var wellKnownSymbol = require('../internals/well-known-symbol'); var V8_VERSION = require('../internals/engine-v8-version'); var SPECIES = wellKnownSymbol('species'); module.exports = function (METHOD_NAME) { // We can't use this feature detection in V8 since it causes // deoptimization and serious performance degradation // https://github.com/zloirock/core-js/issues/677 return V8_VERSION >= 51 || !fails(function () { var array = []; var constructor = array.constructor = {}; constructor[SPECIES] = function () { return { foo: 1 }; }; return array[METHOD_NAME](Boolean).foo !== 1; }); };
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