Return value from a promise

[NilkasG (Niklas Gollenstede)]

I think I explained this quite well here:

Chrome.storage.local is undefined in Firefox

Neither chrome.storage.local.get(...) nor browser.storage.local.get(...) return any data. Both accept a callback as the last parameter and will asynchronously pass their data as an argument to that callback. With browser.storage.local.get(...) you can omit the callback because it also returns a Promise. Promises are special ES6 language objects. Semantically they promise that some value will be avaiable in the future. There are two ways to get that future value: calling .then(...) on the promi…