Interview

What I need for an interview?

https://garfinkleexecutivecoaching.com/downloads/salarynegotiation/book_r7e2k4.pdf

Salary

Angular

What are lifecycle hooks available?
Where is use constructor and ngOnChange?
Content Projection in Angular ?
What is Dependency injection (DI)
What is the difference between pure and impure pipe?
What is the difference between promise and observable?

Node.js

what is object oriented concepts in JavaScript?

Answer

ngOnInit(): This is called when the component is loaded into the DOM and it occurs only once.

ngOnChanges(): This is called when there is Input property to the component and it is called before ngOnInit() and occurs every time there is a change in the input property. It is not called if there is no input property to the component

ngDoCheck(): occurs every time there is a change detection and immediately after ngOnChanges() and ngOnInit().

ngOnDestroy(): This is called right before the component gets destroyed and occurs only once.

ngAfterViewInit(): This is called once after the component’s view/ child views are loaded and right after ngAfterContentChecked() and occurs only once.

ngAfterViewChecked(): This is called after component’s view/ child views are loaded and called after ngAfterViewInit() and every time after ngDoCheck().

ngAfterContentInit(): This is called once external content is projected into component’s view and right after the first ngDoCheck() and occurs only once.

ngAfterContentChecked(): This is called after external content projected into component’s view and called after ngAfterContentInit() and every subsequent ngDoCheck().

React

DUMP COMPONENT : Dumb components are also called ‘presentational’ components because their only responsibility is to present something to the DOM

example :

` const Footer = (props) => { return(

Footer Information

) } `

Smart Components : Smart components (or container components) on the other hand have a different responsibility Because they have the burden of being smart, they are the ones that keep track of state and care about how the app works.

class App extends Component { constructor(props){ super(props); this.state = {pictures : []}; } }

using controlled components to implement forms.
In a controlled component, form data is handled by a React component
The alternative is uncontrolled components, where form data is handled by the DOM itself.

– Container vs Presentational components – Smart vs Dumb compone

That means the stateful components are keeping track of changing data
stateless components print out what is given to them via props, or they always render the same thing

Examples of stateless components being reusable

Can stateful components be reusable?

Class Component

A class component must include the extends React.Component statement. This statement creates an inheritance to React.Component, and gives your component access to React.Component's functions.

The component also requires a render() method, this method returns HTML.

class Car extends React.Component { render() { return <h2>Hi, I am a Car!</h2>; } }

Function component

A Function component also returns HTML, and behaves much the same way as a Class component, but Function components can be written using much less code, are easier to understand, and will be preferred

function Car() { return <h2>Hi, I am a Car!</h2>; }

Certainly, stateful components can be reused.

what is HOC?

A higher-order component (HOC) is an advanced technique in React for reusing component logic. HOCs are not part of the React API, per se. They are a pattern that emerges from React’s compositional nature.
A higher-order component is a function that takes a component and returns a new component.

.NET

oops

class scope - internal
internal and public

encapsulation - hiding the data abstration- showing the relevant data

interface - interface has only signature of class and it has no implementation all class drive inheritance - multiple inheritance support constractor - no constractor static - no static member , all member are public

abstract - abstract class can contain with body and without body. inheritance - multiple inheritance not support , only one class inheritance constractor - default constractor static - static memeber, member are public, private, internal

using System;
interface A
{
void Hello();
}
interface B
{
void Hello();
}
class Test : A, B
{
void A.Hello()
{
Console.WriteLine("Hello to all-A");
}
void B.Hello()
{
Console.WriteLine("Hello to all-B");
}
}
public class interfacetest
{
public static void Main()
{
A Obj1 = new Test();
Obj1.Hello();
B Obj2 = new Test();
Obj2.Hello();
}
}

base keyword is used to access members of the base class from within a derived class base.calculate

SQL

delete duplicate record

delete from dbo.Emp where EmpID not in(SELECT max(EmpID) as id
FROM [Employee].[dbo].[Emp] group by [name])

delete from dbo.Emp where EmpID not in(SELECT min(EmpID) as id
FROM [Employee].[dbo].[Emp] group by [name])

Get Highest 3 record of employee

select top 1 t.salary from (SELECT top 3 [salary] FROM [Employee].[dbo].[Emp] order by salary desc ) as t order by t.salary

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