Interview question one line on Angular

Sl No	Questions	Keyword Answer	Example
1	What does "npm install -g" mean?	To install npm package global level
2	What is Angular CLI	It is command line interface which helps to get basic setup of angular project	npm install -g  @angular/cli ng new project-name cd project-name ng serve
3	How to create app using Angular CLI?	ng new project-name cd project-name code . (to open project in Visual studio code editor) ng serve
4	Differentiate between ng serve and ng builld?	ng serve - Is use to run application in In-memory (inside RAM) taking whole application compling hosted in http://localhost:4200/ ng build - To
5	What do folder "src", "dist" and "e2e" contain?	Src - (source folder) All source code dist - (distribution folder) All build js will be saved after running ng build command e2e - (end to end testing folder) For testing purpose
6	what is importance of angular.json file in Angular cli?	Workspace is a directory which is generated via Angular CLI
7	What are components and modules in Angular	Components - Class file which will interact with UI i.e., html files Modules - Which is used to group components, directives, pipes and services
8	What is use of TemplateURL	which connects components and html page
9	Explain modules	Which is used to group components, directives, pipes and services	@NgModule({    declarations: [       AppComponent    ],    imports: [       BrowserModule    ],    providers: [],    bootstrap: [AppComponent] })
10	What is use of Bootstrap in Modules	Out of many components, Bootstrap helps for starting the execution
11	Which file defines the start module of angular project	Main.ts files PlatformBrowserDynamic method from @angular/PlatformBrowserDynamic  library	platformBrowserDynamic().bootstrapModule(MainModule)
12	What is Import in module	To import angular library to NgModule import statement on top is used by typescript import { FormsModule } from '@angular/forms';	For import statement import { FormsModule } from '@angular/forms'; Import in @NgModule imports: [    BrowserModule,    FormsModule ]
13	What is Provider in module	Will include in services created
14	What will happen if polyfills are not used	make our Angular application compatible for different browsers. Angular code in ES6(New Features: Overview and Comparison) and is not compatible with IE or firefox and needs some environment setups before being able to be viewed or used in these browsers.	Polyfills.ts was provided by angular to help you do away with need to specifically setup everything.
15	What is need of Webpack	Webpack is a module bundler, but you can also use it running tasks as well
16	How to use *ngFor Loop directive	NgFor is a directive that iterates over collection of data
17	Explain ^ and ~ for version resolution	^  Latest minor version ~  Latest revision version	6.1.0 6 is major version 1 is for minor version 0 is for revision version
18	Can we have Angular UI without a component	No
19	What is routing Collection	Routing collection is nothing but where we specify URL and component which is loaded
20	Explaing the importance of [routerLink] in href element	To naviage between routes	<a [router-link]="['home']">Home</a>
21	What is importance of router-outlet element in routing	router-outlet is directive which tell router to render the content in view	<router-outlet></router-outlet>
22	Explain importance of loadChildren	To achieve lazy loading routing
23	How is URL structured for loadChildren	../Customer/CustomerApp.CustomerModule#CustomerModule Customer - folder or path CustomerApp.CustomerModule - Filename or path #CustomerModule - After # Class to be loaded
24	Explain importance for forRoot and forChild	forRoot - For eager loading forChild - For lazy loading
25	What the importance of Dirty Flag, pristine, touched, untouched, valid, invalid	Dirty flag - indicates user has changed values Pristine - opposite of dirty flag Touched - indicates field is touched by user Untouched - Opposite of touched Valid - Checks whether all validation have passed Invalid - opposite of valid
26	When do we need to provide standalone option	Control which is inside FormGroup without validation is to be provide standalone option	[ngModelOptions] = "{ standalone : true }"
27	What is benefit of DI	dependency injection is a technique whereby one object  supplies the dependencies to another object
28	What are two kinds of DI	Centralized DI Conditional DI
29	Explain importance of injector	Injector is used to achieve conditional based DI.
30	Define reusable user controls	Reusable code snipnet of UI which we can plug into any HTML
31	Explain inputs, output and event emittes	@Input is a decorator to mark an input property and @Output is a decorator to mark an output property. EventEmitter is really an Angular abstraction, and should be used pretty much only for emitting custom Events in components
32	which of the below naming convention is good for a custom user control myTextBox my-texbox	my-textbox - because it should not get confict with html tag which might release in future
33	Which notatin will you use when data flows from user control to main UI [] ()	[]
34	How to use HTTP component	To call to server via restful servcie
35	Why DTO is a better way of transferring data	To avoid circular dependency error
36	In new project should we use HTTP or HTTP client	HTTP client HTTP is deprecated from Angular 7
37	What is importance of DI in using HTTP component	As we want to migrate from Angular 6 to 7. We don’t need to change too much of code
38	What are interceptors in httpclient	To set security key in http header call
39	how to create fake server	json-server
40	explain the importance of integrated terminal in VS code?	We can create more terminals like for run fake server via json-server which use port 3000 and other we can use for ng serve to run angular application port 4200	npm install -g json-server json-server --watch db.json