JSON

Question 1

What is JSON?

Answer 1

JS object notation

used to send data btwn computer systems

Question 2

What are serialization and deserialization?

Answer 2

serialization: converting an Object into stream of bytes so that it can be transferred over a network or stored in a persistent storage.
deserialization: Fetch a stream of bytes from network or persistence storage and convert it back to the Object with the same state.

Question 3

Why are serialization and deserialization useful?

Answer 3

pack up and send data

Question 4

How do you serialize a data structure into a JSON string using JavaScript?

Answer 4

JSON.stringify(objectName);

must stringify to send as JSON

Question 5

How do you deserialize a JSON string into a data structure using JavaScript?

Answer 5

JSON.parse(stringName);

must parse to use in JS

Question 6

How to you store data in localStorage?

Answer 6

localStorage.setItem( ‘key’, ‘value’ )

Question 7

How to you retrieve data from localStorage?

Answer 7

localStorage.getItem ( ‘key’ );

Question 8

What data type can localStorage save in the browser?

Answer 8

JSON only - string data for keys and values

Question 9

When does the ‘beforeunload’ event fire on the window object?

Answer 9

before window, document, etc are about to be unloaded. document is visible.