Chapter 5

Question 1

What is the event handler for vanilla JavaScript?

Answer 1

addEventListener

Question 2

What is a touch event?

Answer 2

Any action taken by an application when a gesture is applied

Question 3

What does ‘ontouchstart’ do?

Answer 3

It is an event that will trigger when someone is using a touch screen and touches the screen to start

Question 4

What does API stand for?

Answer 4

Application Programming Interface

Question 5

Now, define what API is

Answer 5

An API is a set of routines, protocols, and tools that we use to build apps. Specifically for programming graphical user interface elements otherwise known as GUI elements.

Question 6

What is a Web Worker?

Answer 6

These are APIs that allows scripts to run background in parallel; they connect to multiple webpages to get real-time data. From Mozilla Developers network:
Web Workers makes it possible to run a script operation in a background thread separate from the main execution thread of a web application. The advantage of this is that laborious processing can be performed in a separate thread, allowing the main (usually the UI) thread to run without being blocked/slowed down.

Question 7

What is a Web Socket?

Answer 7

An API with consistent communication between a client and a web server.

Question 8

What is full-duplex communication?

Answer 8

It’s an old networking term that means two devices connected to a network can communicate back and forth at the same time

Question 9

Geolocation API

Answer 9

an interface that uses latitude and longitude coordinates to provide a devices’ location

Question 10

What is a try-catch sequence?

Answer 10

Try to do something, if it doesn’t work we’ll catch an error message and if we do catch an error message we want something else to happen

Question 11

What are the main events associated with WebSocket communcations

Answer 11

onopen: when a socket opens
onmessage: when the web server receives a message
onclose: when a socket closes

Question 12

File API

Answer 12

Used for uploading files from local storage to remote server

Question 13

Web Storage

Answer 13

Saves session data within the browser or device memory. The sessionStorage() method keeps data until the browser is closed (for one session) localStorage() saves large data persistently (session-to-session).

Question 14

Local storage

Answer 14

Used to save persistent data. It is stored in key/value pairs. It is browser-specific

Question 15

Hardware capabilities

Answer 15

GPS
Accelerometer
Camera

Question 16

JavaScript is a

Answer 16

• dot notation scripting language used to enhance web pages

Question 17

Steps involved in creating an app are:

Answer 17

Plan your project
Design the user interface
Update the manifest file
Write Code
Build the app
Debug and test
Package
Validate
Deploy

Question 18

What is an App package

Answer 18

A file that explains what files are needed in order for an app to run properly.

Question 19

What is a process?

Answer 19

A process is a program that’s being executed

Question 20

What is state management

Answer 20

It is maintaining browser data

Question 21

App state

Answer 21

Starts when a web browser sends the first request for a webpage to a web server

Question 22

Session state

Answer 22

Happens when the first request for an application opens a session, and ends when we close the session

Question 23

Persistent state

Answer 23

Refers to the data an application needs after a session ends and this data is used the next time one gets on a website

Question 24

localStorage

Answer 24

Data is stored from session to session without any time limit

Question 25

sessionStorage

Answer 25

data is stored only for one session, and once the browser closes that session is deleted

window.sessionStorage

Save data to sessionStorage:
sessionStorage.setItem(“key”, “value”);

Read sessionStorage data:
var name = sessionStorage.getItem(“key”);

Question 26

App Container

Answer 26

A memory space in which an app can run without interference from other apps

Question 27

App Package

Answer 27

The result of compressing files and folders into a single file which can then be installed as an app. An executable

Question 28

ALM

Answer 28

Application Lifecycle Management