SOURCE

var groupAnagrams = function(strs) {

    var m = new Map();
    var list = strs.map((e,index)=>{
        return [e.split('').sort().join(),index]
    }).forEach(e=>{
        if(m.has(e[0]))
          m.get(e[0]).push(strs[e[1]]);
        else
           m.set(e[0],[strs[e[1]]]);
    });
    return list;
};
console.log(
    groupAnagrams(
         ["eat", "tea", "tan", "ate", "nat", "bat"]
    )
)

<p>jj</p>