History of WeakMap Revision history for: English (US) Català 14 nov. 2015, 4:29:15 enTropy Previous 14 nov. 2015, 2:54:46 llue Previous 13 nov. 2015, 11:17:21 llue 30 set. 2015, 14:17:45 LPGhatguy Chrome, as of at least 45+, throws when using WeakMap() without `new`. I'm not sure when this was introduced.