Problems to get the data from Ionic Storage

Question

I have a problem with the Ionic-Storage. I want to save a boolean into the storage. The action is triggered by an ion-toggle. If the toggle is on= true, otherwise false. So I have create a service, which can save and get the data.

Storage-Service.ts

const ITEM_KEY = 'modal-myworkplace';
[...]


async setItem(value){
  const res = await this.storage.set(ITEM_KEY,value)
   console.log(res)
 }

  async getItem() {
      await this.storage.get(ITEM_KEY).then((name) => {
          console.log('The Keyvalue is: '+name)
      })
  }

Here is the problem... I want to get this data in an component. Like this: Component.ts

let saveWorkplace: boolean;
[...]
async setData(){
    await this.storage.getItem().then((name) => {
      console.log("Key: "+ name)
    })
  }

I want to get the value from the Storage (true or false) and this should then be defined in saveWorkplace.

If I console.log this properties in the Component.ts I get an undefined object. But if i console.log the property in Storage.ts I get an Value( See Image )

I dont know how I can get only the Value true or false.

I hope anyone can help me

Answer 1

Your getItem() is not returning the value. Change it to:

async getItem() {
    return await this.storage.get(ITEM_KEY);
}

Answer 2

You need to make sure you track what you return (Promise or value) and update your code accordingly:

Service:

setItem(value):Promise<any> {

  this.storage.set(ITEM_KEY,value) // you can use .then here to check saved value.

}

getItem():Promise<any> {

  return this.storage.get(ITEM_KEY);

}

In your component since you are returning promise you can use async:

async getData() {

  return this.saveWorkplace = await this.storage.getItem()

};

Now if you feel the need to leverage async method and read these values at the page initialization time (ngOnInit), you can do so this way:

ngOnInit() {
    this.getData().then( saved => {
        console.log(saved)
        // the rest of init code that depends on the value;

    })
};