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- var anObject = require('../internals/an-object');
- var aFunction = require('../internals/a-function');
- var wellKnownSymbol = require('../internals/well-known-symbol');
- var SPECIES = wellKnownSymbol('species');
- // `SpeciesConstructor` abstract operation
- // https://tc39.es/ecma262/#sec-speciesconstructor
- module.exports = function (O, defaultConstructor) {
- var C = anObject(O).constructor;
- var S;
- return C === undefined || (S = anObject(C)[SPECIES]) == undefined ? defaultConstructor : aFunction(S);
- };
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