Call back and error handling

Question 1

first class function

Answer 1

treating functions like variables and passing around

Question 2

closure

Answer 2

a function defined inside another function has access to all the variables declared in the outer function (outer scope)

the inner function will continue to have access to the variables from the outer scope even after the outer function has returned

Question 3

single threaded event loop

Answer 3

picks a request from queue
service that request
some request may trigger io opperation
branch off and continue the execution of next request

Question 4

node convention to write callback function

Answer 4

very first parameter must be always error

Question 5

throw an error

Answer 5

throw new Error “string”

Question 6

Yargs

Npm install yargs –save

Answer 6

Supports command line arguments to be supplied to node aplication

Question 7

………. variable determines the export from the current module

Answer 7

Module.exports

Question 8

The ……… function is used to import a module

Answer 8

Require