text: 'use strict';
  var $export = require('./_export');
  var toObject = require('./_to-object');
  var toPrimitive = require('./_to-primitive');
  var toISOString = require('./_date-to-iso-string');
  var classof = require('./_classof');
  
  $export($export.P + $export.F * require('./_fails')(function () {
    return new Date(NaN).toJSON() !== null
      || Date.prototype.toJSON.call({ toISOString: function () { return 1; } }) !== 1;
  }), 'Date', {
    // eslint-disable-next-line no-unused-vars
    toJSON: function toJSON(key) {
      var O = toObject(this);
      var pv = toPrimitive(O);
      return typeof pv == 'number' && !isFinite(pv) ? null :
        (!('toISOString' in O) && classof(O) == 'Date') ? toISOString.call(O) : O.toISOString();
    }
  });
  