Balanced Bracked solution v2

balanced_braket_v2.js

function isBalanced(s) {
    // Write your code here
    let agg = "";
    let mapping = {"{": "}", "[": "]", "(": ")"};
    let validBraces = ["()", "{}", "[]"];
    for(let c of s){
        //Check if opening
        if(mapping[c]){
            agg += c;     
        }else{
            //check if match last opening
            let opening = agg.substr(-1);
            let brace = opening + c;
            if(validBraces.includes(brace)){
                agg = agg.substr(0, agg.length -1)
            }else{
                return "NO"
            }
        }
    }
    return (agg == "") ? "YES" : "NO";
}