Clarification on Conference app code

Ionic Framework ionic-v3
1

I go through
https://github.com/driftyco/ionic-conference-app/blob/master/app/pages/schedule/schedule.js

but not understand why bellow code written and what is advantage of the code

static get parameters() {
    return [[IonicApp], [NavController], [ConferenceData], [UserData]];
  }
2

Yea, i don’t understand at all what that means but… as far as i understand, this:

export class SchedulePage {
  static get parameters() {
    return [[IonicApp], [NavController], [ConferenceData], [UserData]];
  }

  constructor(app, nav, confData, user) {
    this.app = app;
    this.nav = nav;
    this.confData = confData;
  }

is similar to this (i think):

  constructor(app: IonicApp, nav: NavController, confData: ConferenceData, user: UserData) {
    this.app = app;
    this.nav = nav;
    this.confData = confData;
  }

I had to use the first method (becouse of errors) before i changed to TypeScript (ionic start “nam” --v2 --ts)

3

This is how you would inject dependencies in pure ES6:

static get parameters() {
    return [[IonicApp], [NavController], [ConferenceData], [UserData]];
}

constructor(app, nav, confData, user) {
    // ...
}

As @aluknot mentioned it’s an equivalent of the following TypeScript code:

constructor(app: IonicApp, nav: NavController, confData: ConferenceData, user: UserData) {
    // ...
  }

Angular 2 Dependency Injection (the guide is currently only for TypeScript though).