Prototype dan Strict mode pada JavaScript

Ada yang ngerti apa itu prototype di javascript? berikut contoh kodingannya

'use strict';
function FriendlyChat() {
  this.initFirebase()
}

FriendlyChat.prototype.initFirebase = function() {
  // Shortcuts to Firebase SDK features.
  this.auth = firebase.auth();
  this.database = firebase.database();
  this.storage = firebase.storage();
  // Initiates Firebase auth and listen to auth state changes.
  this.auth.onAuthStateChanged(this.onAuthStateChanged.bind(this));
};

Pertanyaan tambahan pada kode diatas, apakah penggunaan this this this this dst karena menggunakan mode strict ?