core-js/modules/es.set.difference.v2.js

Standard library

'use strict';
var $ = require('../internals/export');
var difference = require('../internals/set-difference');
var fails = require('../internals/fails');
var setMethodAcceptSetLike = require('../internals/set-method-accept-set-like');

var SET_LIKE_INCORRECT_BEHAVIOR = !setMethodAcceptSetLike('difference', function (result) {
  return result.size === 0;
});

var FORCED = SET_LIKE_INCORRECT_BEHAVIOR || fails(function () {
  // https://bugs.webkit.org/show_bug.cgi?id=288595
  var setLike = {
    size: 1,
    has: function () { return true; },
    keys: function () {
      var index = 0;
      return {
        next: function () {
          var done = index++ > 1;
          if (baseSet.has(1)) baseSet.clear();
          return { done: done, value: 2 };
        }
      };
    }
  };
  // eslint-disable-next-line es/no-set -- testing
  var baseSet = new Set([1, 2, 3, 4]);
  // eslint-disable-next-line es/no-set-prototype-difference -- testing
  return baseSet.difference(setLike).size !== 3;
});

// `Set.prototype.difference` method
// https://tc39.es/ecma262/#sec-set.prototype.difference
$({ target: 'Set', proto: true, real: true, forced: FORCED }, {
  difference: difference
});