hashtable - How do I look up the key in a hash by its value? (JavaScript) -

i have small program below takes array of strings input, say, ["abc","defg","z","hijk"]. strings taken 1 one , stored in hash, respective lengths recorded next them. eg---> { abc: 3, defg: 4, z: 1, hijk: 4 }

a new array formed, , values of keys created goes it. max number removed twice. third max value 1 have grabbed. have it, how call associated key returned, please?

so example: if strarr ["abc","defg","z","hijk"], because "abc" 3 chars, return 3, "abc". how refer "abc" in above hash it's value?

for illustrative example, if strarr happened ["hello", "world", "before", "all"] ultimate output should 5 associated world because "before" 6 letters long, , "hello" , "world" both 5, output should world because appeared last 5 letter word in array.

 var hashobject = {};  var strarr = ["abc","defg","z","hijk"];   function thirdgreatest(strarr) {     var count = 0;     for(var = 0; i<strarr.length; i++) {         var cur = strarr[i];         var curlen = cur.length;         hashobject[cur] = curlen;      }     console.log(hashobject);     var newarr = [];      for(var x = 0, keys = object.keys(hashobject), xx = keys.length; x < xx; x++) {         var val = hashobject[keys[x]];         newarr.push(val); //here form array of key values above     }      console.log(newarr);      for(var j = 0; j < 2; j++) {         console.log(newarr);         newarr.splice(newarr.indexof(math.max.apply(math,newarr)),1); //here remove max value 2 times       }         return math.max.apply(math,newarr); //this 3rd largest string's value.         //but how use return key associated instead, please?   }    console.log(thirdgreatest(strarr));