Ionic2 load rows from sqlite after database ready - sqlite

Question

I have an ionic 2 app with a database service powered by sqlite. The database stores a couple rows of items. The first page of the app displays those items. The issue I'm running into is that the page attempts to load the items before the service has loaded the database. I get this error:
Cannot read property 'executeSql' of undefined
If i navigate to a different page and back to home, it loads correctly. This is the database service. I'm attempting to call getScanables on the first page.
import { Injectable } from '#angular/core';
import {SQLite} from 'ionic-native';
import {Platform} from 'ionic-angular';
#Injectable()
export class Database {
private storage: SQLite;
public isOpen: boolean;
public constructor(private platform: Platform,) {
console.log('Creating storage.');
platform.ready().then(() => {
console.log('Platform Ready.');
if(!this.isOpen) {
console.log('Database Unopened');
this.storage = new SQLite();
this.storage.openDatabase({name: "data.db", location: "default"}).then(() => {
console.log('Generating Database');
this.storage.executeSql("CREATE TABLE IF NOT EXISTS scanables (id INTEGER PRIMARY KEY AUTOINCREMENT, value TEXT, type TEXT, name TEXT, date TEXT)", []);
//this.storage.executeSql("CREATE TABLE IF NOT EXISTS journal (id INTEGER PRIMARY KEY AUTOINCREMENT, role TEXT, descriptors TEXT, image TEXT, behaviors TEXT)", []);
console.log('Generated.');
this.isOpen = true;
}, (error) => {
console.log("Error opening database.", error);
});
}
});
}
public getScanables() {
console.log('Getting Scanables');
return new Promise((resolve, reject) => {
this.storage.executeSql("SELECT * FROM scanables", []).then((data) => {
let journal = [];
if(data.rows.length > 0) {
for(let i = 0; i < data.rows.length; i++) {
journal.push({
id: data.rows.item(i).id,
value: data.rows.item(i).value,
type: data.rows.item(i).type,
name: data.rows.item(i).name,
date: data.rows.item(i).date,
letter_one: data.rows.item(i).name.substring(0,1)
});
}
}
resolve(journal);
}, (error) => {
reject(error);
});
});
}
...
}
This is the relevant code for the first page:
#Component({
templateUrl: 'journal.html'
})
export class JournalPage implements AfterViewInit {
public orderType: string = 'delivery';
public autocomplete: {term: string, place: any};
public regions: any;
public itemList: Array<Object>;
public addList: Array<number>;
constructor(private navCtrl: NavController,
private menu: MenuController,
private modalCtrl: ModalController,
private database: Database,
public userService: UserService,
private helper: Helper,
private l: LoggerService) {
this.itemList = [];
this.addList = [1,2,3,4,5,6,7];
}
ngAfterViewInit(): any {
console.log('journal.ngAfterViewInit');
this.load();
}
public load() {
console.log('journal.load');
this.database.getScanables().then((result) => {
console.log('entered getScanables');
this.itemList = <Array<Object>> result;
console.log('itemList', this.itemList);
}, (error) => {
this.l.error('journal.ts:', error);
});
}
...

Answer 1

The solution for this issue was to make the service's database a public variable and load the database on load. Then only after loading the database we set the root page. This forces the database to load first. May not be the ideal solution though, so feel free to post additional answers.