My solution for day 7 puzzle at adventofcode.com

advent-of-code-day-7.js

let data = `xdsqxnovprgovwzkus[fmadbfsbqwzzrzrgdg]aeqornszgvbizdm
itgslvpxoqqakli[arktzcssgkxktejbno]wsgkbwwtbmfnddt[zblrboqsvezcgfmfvcz]iwyhyatqetsreeyhh
...
kpglgg[mpvkikuabwucwlpqf]cmzkcdnrhwjmfgbmlq
spwwppgjgfexuezrixp[rotgzyxzqxyrroafx]tkwxfiamzdjdqpftvq`;

let dataArray = data.split(/\n/);
// finds ABBA pattern in square brackets
let inBracketsRegEx = /(?=\[[a-z]*([a-z])([a-z])\2\1[a-z]*\])(?!\[[a-z]*([a-z])\1{3}[a-z]*\])/;
// finds ABBA pattern
let matchRegEx = /(?=([a-z])([a-z])\2\1)(?!([a-z])\1{3})/;

dataArray = dataArray.filter( address => !inBracketsRegEx.test(address) );
dataArray = dataArray.filter( address => matchRegEx.test(address) );

console.log(dataArray.length);