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