Обход свойств JavaScript-объекта.

loop-through-object.js

var myObject = {
  "key_1": "value_1",
  "key_2": "value_2",
  "key_n": "value_n"
};

for (var keyName in myObject) {
  if (myObject.hasOwnProperty(keyName)) {

    // Do something:
    localStorage.setItem(keyName, myObject[keyName]);
    
  }
}