2 var $ = require('../internals/export');
3 var IS_PURE = require('../internals/is-pure');
4 var $upsert = require('../internals/map-upsert');
6 // `WeakMap.prototype.upsert` method
7 // https://github.com/thumbsupep/proposal-upsert
8 $({ target: 'WeakMap', proto: true, real: true, forced: IS_PURE }, {