Data from API

Question 1

Distributed Computing

Answer 1

It allows 2 diff apps running on 2 diff machines to share info. it also allows 2 diff objects running in 2 diff process on same machine to share info.
Distributed technologies
- CORBA - Common Request Broker Architecture (14 languages)
- DCOM - Distributed Component Object Model - VB
- RMI - Remote Method Invocation - J2EE
- EJB - Enterprise Java Beans - Java
- Web Service - All technologies
- Remoting - .Net

Question 2

Computing Architecture

Answer 2

Question 3

Web Service Specification

Answer 3

1. SOAP
2. REST
3. JSON

Question 4

SOAP

Answer 4

Service Oriented Architecture Protocol
- Consumer sends XML request
- Provicer sends XML response

Question 5

REST

Answer 5

Representational State Transfer
- Consumer sends a query request
- Provider sends XML response, optionally JSON
-?category=electronics

Question 6

JSON

Answer 6

JavaScript Object Notation
Consumer and provider use JSON

Question 7

API

Answer 7

Question 8

JavaScript API

Answer 8

Question 9

XMLHttpRequest

Answer 9

JS object used to communicate with an end point. it provides props and methods to handle communication.
var http = new XMLHttpRequest(); (BOM object)

Question 10

XMLHttpRequest - open()

Answer 10

Question 11

XMLHttpRequest - send()

Answer 11

Question 12

XMLHttpRequest - Life Cycle Methods

Answer 12

onreadystatechange - f()
It executes the AJAX function and identifies the result. It defines actions to perform when response is ready.
It depends on “readystate” status, which includes
0: Initial
1:Pending
2:Processing
3:Completed
4:Ready [Response Ready]

responseText : returns string response
responseXML : returns XML response
responseHTML : returns HTML response

Question 13

XMLHttpRequest - Drawbacks

Answer 13

XMLHttpRequest object doesn’t offer native support for synchronous requests, leading to potential blocking of the UI while waiting for a synchronous response.
No Built-in Support for Promises: XMLHttpRequest doesn’t natively support modern features like Promises, which can make code harder to read and maintain, especially when dealing with multiple asynchronous operations.
Explicit async config is required
the response is not directly in JSON format
It requires explicit parsing methods [JSON.parse()]
It is poor in error handling (cant track client and server side errors implicitly)

Question 14

JavaScript Fetch Promise

Answer 14

Fetch is JS window object method
It is a promise.
It is implicitly Async
It provides implicit catch method, but cant catch the issues
It requires an explicit “throw”
It returns daat in binary format
Explit data parsing is required

fetch(“url”).then().catch().finally()

Question 15

JQuery Ajax

Answer 15

Syntax:
$.ajax({
method:””,
url:””,
data:{},
success: (),
error: ()
})

Question 16

axios

Answer 16

An external library to make API calls and has rich error handling

Question 17

How can you know about the keys in any unknown object ?

Answer 17

1. Object.keys() => returns the array of all keys in a object
   Object.keys(objName).map(function(key) {
   typeof objName[key]
   })
2. for .. in iterator
   for(var prop in object)
   {}