Javascript beats 100%  in memory usage always and 100% in performance sometimes
javascript\n/**\n * @param {string[]} emails\n * @return {number}\n */\nvar numUniqueEmails = function(emails) {\n    const r = /(\\.(?=[^@]+@))|(\\+.+(?=@))/g;
```javascript\n/**\n * @param {string[]} emails\n * @return {number}\n */\nvar numUniqueEmails = function(emails) {\n    const r = /(\\.(?=[^@]+@))|(\\+.+(?=@))/g;\n    return new Set(emails.map((item) => {\n        return item.replace(r, \'\');\n    })).size;\n};\n```
['Ordered Set', 'JavaScript']