JavaScript | Time: O(N)
Please upvote, if it helps you!\n\n\nvar numUniqueEmails = function(emails) {\n    let uniqueEmails = new Set()\n    \n    function removeCharsAfterPlus(email) 
## Please upvote, if it helps you!\n\n```\nvar numUniqueEmails = function(emails) {\n    let uniqueEmails = new Set()\n    \n    function removeCharsAfterPlus(email) {\n        let [localName, domain] = email.split(\'@\')\n        localName = localName.split(\'+\')[0]\n        return localName + \'@\' + domain\n    }\n    \n    function getCharsWithoutDots(email) {\n        let [localName, domain] = email.split(\'@\')\n        localName = localName.split(\'.\').join(\'\')\n        return localName + \'@\' + domain\n    }\n    \n    for (let email of emails) {\n        email = removeCharsAfterPlus(email)\n        email = getCharsWithoutDots(email)\n        uniqueEmails.add(email)\n    }\n    \n    return uniqueEmails.size\n};\n```
['Ordered Set', 'JavaScript']