IONIC 3 new local storage

Question

I want to create a new localstorage in my ionic app (IONIC 3), but I've looked many ways to do that. I currently have this:

database.ts (my provider)

import { HttpClient } from '@angular/common/http';
import { Injectable } from '@angular/core';

import { Storage } from '@ionic/storage';

@Injectable()
export class DatabaseProvider {


  localData: Storage;

  constructor(public http: HttpClient) {


    this.localData = new Storage(localStorage);
  }



}

but the IDE told me that it's a mistake in the line "this.localData = new Storage(localStorage);" maybe it requires a special import. I have installed the "@ionic/storage": "2.1.3".

Thanks for your help!

Answer 1

You do not need to provide an argument to storage constructor unless you want to specify settings like the perferred db. Here is an example of using Storage in a provider-

LocalNotes.ts

import {Injectable} from '@angular/core';
import {Storage} from '@ionic/storage';


@Injectable()
export class LocalNotes {
  local:any;

  constructor() {
    this.local = new Storage();
  }

  getNotes() {
    return new Promise((resolve, reject)=> {
      this.local.get('userNotes')
        .then((answer)=> {
          resolve(answer);
        })
        .catch((err) => {
          reject(err);
          });
      });
  }

  setNotes(notes:string[]) {
    this.local.set('userNotes', notes);
  }    
}

Answer 2

I am using sql storage 2.2 and so far I havent had any problem

Install it as

ionic cordova plugin add cordova-sqlite-storage

then

npm install --save @ionic/storage

As for the documentation Ionic Storage you need to add the storage service to your module

import { IonicStorageModule } from '@ionic/storage';
@NgModule({
  declarations: [
    // ...
  ],
  imports: [
    BrowserModule,
    IonicModule.forRoot(MyApp),
    IonicStorageModule.forRoot()<---------- THIS
  ],
  bootstrap: [IonicApp],
  entryComponents: [
    // ...
  ],
  providers: [
    // ...
  ]
})
export class AppModule {}

then you could use it like this

        import { HttpClient } from '@angular/common/http';
        import { Injectable } from '@angular/core';
        import {Observable} from "rxjs/Observable";
        import 'rxjs/add/observable/fromPromise';
        import { Storage } from '@ionic/storage';

        @Injectable()
        export class DatabaseProvider {
          constructor(public http: HttpClient, private _storage:Storage) {
          }
          getData(keyName:string):Observable<any> {
           return  Observable.fromPromise(this._storage.get('keyName'));
         }
          setData(keyName:string,data:any):Observable<any>{
           return  Observable.fromPromise(this._storage.set(keyName,JSON.stringify(data)));
         }
     }

Please have in mind I just wrote this based on working solution but this is not tested