node_modules/core-js/modules/_enum-keys.js

// all enumerable object keys, includes symbols
var getKeys = require('./_object-keys');
var gOPS = require('./_object-gops');
var pIE = require('./_object-pie');
module.exports = function (it) {
  var result = getKeys(it);
  var getSymbols = gOPS.f;
  if (getSymbols) {
    var symbols = getSymbols(it);
    var isEnum = pIE.f;
    var i = 0;
    var key;
    while (symbols.length > i) if (isEnum.call(it, key = symbols[i++])) result.push(key);
  } return result;
};