Store an array with chrome.storage.local
I think you've mistaken localStorage for the new Chrome Storage API.
- You needed JSON strings in case of the localStorage
- You can store objects/arrays directly with the new Storage API
// by passing an object you can define default values e.g.: []chrome.storage.local.get({userKeyIds: []}, function (result) { // the input argument is ALWAYS an object containing the queried keys // so we select the key we need var userKeyIds = result.userKeyIds; userKeyIds.push({keyPairId: keyPairId, HasBeenUploadedYet: false}); // set the new array value to the same key chrome.storage.local.set({userKeyIds: userKeyIds}, function () { // you can use strings instead of objects // if you don't want to define default values chrome.storage.local.get('userKeyIds', function (result) { console.log(result.userKeyIds) }); });});