Callback returns undefined with chrome.storage.sync.get

Question

I\'m building a Chrome extension and I wrote this code.

var Options = function(){};

Options.prototype = {

    getMode: function(){
               return ch         


        

Answer 1

Chrome storage API is asynchronous and it uses callback, that's why you're getting this behavior.

You can use Promise API to overcome this asynchronous issue, which is simpler and cleaner. Here is an example:

async function getLocalStorageValue(key) {
    return new Promise((resolve, reject) => {
        try {
            chrome.storage.sync.get(key, function (value) {
                resolve(value);
            })
        }
        catch (ex) {
            reject(ex);
        }
    });
}

const result = await getLocalStorageValue("my-key");