Retrieve localstorage value when value is change in Ionic 2

Question

I am using ionic 2 framework and I have tried using local storage to store a network status

this.local = new Storage(LocalStorage);
this.local.set(\"status\"         


        

Answer 1

This can be achieved with a BehaviorSubject along with the Storage module from Ionic.

Create a BehaviorSubject that you call .next() whenever you set a key in Storage and subscribe to that BehaviorSubject to get the updated value.

A code example of this:

let storageObserver = new BehaviorSubject(null)

this.storage.set("key", "data")
storageObserver.next(null)

setTimeout(() => {
  this.storage.set("key", "new data")
  storageObserver.next(null)
}, 5000)

storageObserver.subscribe(() => {
  this.storage.get("key")
    .then((val) => console.log("fetched", val))
})

This will set a key in local storage which will be logged to the console, and asynchronously update that key after 5 seconds which then will be logged again to the console. You could refactor the setting of the key and updating the BehaviorSubject to a function.