Search a JavaScript Object

findObject.js

function findKey(obj, searchValue){
  for (var key in obj){
    if (_.has(obj, key) && obj[key]==searchValue){
      return key;
    }
  }
}

findKey({a:1,b:2,c:3},3);//-->'c'

function findKey2(obj, searchValue){
  var ret=[];
  for (var key in obj){
    if (_.has(obj, key) && obj[key]==searchValue){
      ret.push(key);
    }
  }
  return ret;
}

findKey2({a:1,b:2,c:3},3);//-->['c']

function findKey3(obj, searchValue){
  _.reduce(obj,function(memo, value, key){if(value==searchValue)memo.push(key); return memo},[])
}

findKey3({a:1,b:2,c:3},3);//-->['c']