var getKeys = require('./_object-keys')
, toIObject = require('./_to-iobject');
module.exports = function(object, el){
var O = toIObject(object)
, keys = getKeys(O)
, length = keys.length
, index = 0
, key;
while(length > index)if(O[key = keys[index++]] === el)return key;
};