I'm writing a chrome extension and trying to store and retrieve some data for that extension using the chrome.storage API.

Permissions set correcty :

"permissions": ["storage"]

However, as I use chrome.storage.sync.get to retrieve the data, the object I create to be returned by my getValues() function seems to be undefined :

function getValues() {
    let user_data = {};
    chrome.storage.sync.get(['amount', 'totalAmount', 'keywords'], (result) => {
        user_data.amount = result.amount || 0;
        user_data.totalAmount = result.totalAmount || 0;
        user_data.keywords = result.keywords || [];
    })
    console.log(user_data);
    return user_data;
};

getValues();

Has I read in questions/17546953, console.log(Object) updates the displayed Object if its value changed and this is what I get in the console after expanding it (as expected) :

{}
  amount: 0
  > keywords: (4) ['word1', 'word2', 'word3', 'word4']
  totalAmount: 0
  > [[Prototype]]: Object

But I get errors in other functions of my script that are calling getValues() since the returned object always seems empty.

So I try using JSON.stringify() to display the actual value of that object the moment I logged it :

function getValues() {
    let user_data = {};
    chrome.storage.sync.get(['amount', 'totalAmount', 'keywords'], (result) => {
        user_data.amount = result.amount || 0;
        user_data.totalAmount = result.totalAmount || 0;
        user_data.keywords = result.keywords || [];
    })
    console.log(JSON.stringify(user_data));
    return user_data;
};

getValues();

And I get an empty object displayed :

{}

I tried to define the object manually with some dummy values and it works fine : I get {"amount":5,"totalAmount":10,"keywords":["one","two","three"]} in the console as expected.

I looked for similar questions and I read some interesting things; has this something to do with "asynchronous function" ? (I'm very new to javascript and don't know these, yet)

How can I make a function to retrieve the stored object with chrome.storage.sync and return it without that problem ?