Quick answers to Angular2+ Interview Questions
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The document provides quick answers to common Angular interview questions, focusing on Angular 2+ concepts such as components, directives, services, and data binding. It addresses various technical topics including dependency injection, routing, lifecycle hooks, and the differences between observables and promises. The content serves as a condensed guide for individuals preparing for Angular-related interviews.
Quick answers to Angular2+ Interview Questions
- 1. Quick Answers to ANGULAR Interview Questions
- 2. QUICK ANSWERS Here are some answers to common Angular interview questions. That's Angular 2+, not AngularJS. They’re quick, not really extended and are not in any particular order. Let’s get it on!
- 3. Answer: A Web Client Side framework that runs on Typescript. 1) What's Angular?
- 4. Answer: Modules, Components, Templates, Directives, Data Binding, Services, Dependency Injection & Routing 2) Which are the Angular Building Blocks?
- 5. Answer: Compiling from TypeScript to Javascript 3) What's transpiling?
- 6. Answer: ngOnChanges 4) Which execution component triggers on data-bound input updates?
- 7. Answer: A Component is a web application small part. A Directive adds functionality to a DOM element. 5) What's the difference between Components and Directives?
- 8. Answer: A Directive to pass data to a child component. 6) What's the @Input decorator?
- 9. Answer: A Directive to set an event to which a parent component can subscribe. 7) What's the @Output decorator?
- 10. Answer: It's a Directive to put some html content inside DOM element. 8) What's ng-content?
- 11. Answer: A method in the Router service that allow us to navigate to component in a Single-Page-Application. 9) What's router.navigate?
- 12. Answer: A method to encapsulate styles in a component, and has three types: Emulated to allow other's components styles, Native to ignore other component's styles and None to allow other's components visibility. 10) Wha'ts ViewEncapsulation?
- 13. Answer: A shared clas, code that we can use across components. 11) What's a Service
- 14. Answer: It's a pattern that allow us to provide dependencies during runtime asking rather than creating. It's a way to instance once and pass by reference in any other call. 12) What's Dependency Injection?
- 15. Answer: It's a way to emulate navigation in SPA's. 13) What's Routing?
- 16. Answer: It's a Directive that allow us to render the components at an specific location. 14) What's a RouterOutlet?
- 17. Answer: With (event)="method()" Directive to route the event to a TS method. 15) How to handle Events?
- 18. Answer: String Interpotation: The content between the double curly brackets is evaluated and the result replaces the string. 16) What's {{}}?
- 19. Answer: Property, Event, Two Way & String Interpolation. 17) Which are the DataBinding types?
- 20. Answer: OnChange -> OnInit ->DoCheck -> AfterContentInit -> AfterContentChecked -> AfterViewInit -> AfterViewChecked -> OnDestroy. 18) What's the Life-cycle Hooks sequence?
- 21. Answer: It's a dependencies & configuration file that contains information about the current package, its dependencies and their versions 19) What's package.json?
- 22. Answer: A Single-Page-Application, an entire application in a single html page using javascript to emulate navigation and to content the whole app logic. 20) What's a SPA?
- 23. Answer: It's a small part of the application, an HTML block able to be bound to data. 21) What's a Component?
- 24. Answer: It's a directive for two-way data binding. 22) What's NgModel?
- 25. Answer: It's a method for subscription to an event, in order to trigger a function when it happens. 23) What's subscribe?
- 26. Answer: Observables are lazy, they wait till the events occurs and can handle may subscriptions. Promises are eager, immediatly executes and handle a single event. 24) What's the difference between Observables & Promises?
- 27. Answer: It's a Directive that allow us to bind data asynchronously in a string interpolation, using a Promise or Observable directly instead of a property or variable. 25) What's an AsyncPipe?
- 28. Answer: It's using an API on the server side to validate credentials and return a JWT. 26) What's authentication?
- 29. Answer: It's validating access to components or specific data for a specific user in the client side application. 27) What's authorization?
- 30. Answer: It's compiling typescript and html files into Javascript on build time. 28) What's AOT compilation?
- 31. Answer: It's a library that uses the Store pattern to access global data client side in the application. 29) What's Redux?
- 32. Answer: Directives that allow us to format the result in a String Interpolation. 30) What's pipes?
- 33. Answer: ngClass loads a css class, ngStyle sets css styles. 31) What's the difference between ngClass and ngStyle?
- 34. Answer: Functions that allow a building block to be configured before to be used, adding metadata to the object. 32) What's a decorator?
- 35. Answer: The equivalent to the arguments object in Javascript to handle the arguments array. 33) What's a rest parameter?
- 36. Answer: *ngFor="let item of collection" 34) What's the ngFor syntax?
- 37. Answer: FormsModule 35) What's the ngModel module?
- 38. Answer: ReactiveFormsModule 36) What's the ReactiveForms module?
- 39. Answer: ReactiveFormsModule 36) What's the ReactiveForms module?
- 40. Answer: e = new EventEmitter<type>(); 37) How to define custom event?
- 41. Answer: A Decorator to access HTML element alias in a component 38) What's @ViewChild?
- 42. Answer: Template Driven uses two-way data binding, automatic track of data while Reactive Forms is event based. 39) Difference between Template Driven Forms & ReactiveForms?
- 43. Answer: Validator are pre-build functions to handle form validations like min, max, required, etc. 40) What's Validators?
- 44. Answer: A Provider is a Service. 41) What's a Provider?
- 45. Answer: It's a method that returns an NgModule and its provider dependencies. 42) What's 'forRoot'?
- 46. Answer: It's a way to not load every module at once, but on demand, using 'loadChildren' instead of 'component' in routing. 43) What's Lazy Loading?
- 47. Answer: A function's parameter that may not be specified when calling the function. 44) What's an optional parameter?
- 48. Answer: It's Javascript runtime environment, able to run Javascript browserless, as an interpreter. 45) What's NodeJS?
- 49. Answer: It's package manager for NodeJS, able to install and manage dependencies for Javascript projects. 46) What's NPM?
- 50. Answer: It's the module bundler used by angular. 47) What's Webpack?
- 51. Answer: Create, Render, Create and Render childs, Check databoubd changes & re-render & destroy. 48) What's Angular Component Life Cycle?
- 52. Answer: It's an object that represents the data emitted by an event. 49) What's $event?
- 53. Answer: A Decorator to describe a module. 50) What's NgModule?
- 54. Answer: It's a hook, a function trigger for a specific moment, ngOnInit happens after first display of data-bound properties and setup of directives. 51) What's ngOnInit?
- 55. Answer: Unit testing validate isolated pieces of code & E2E validate an integrated set of components. 52) Difference between Unit & E2E testing
- 56. Answer: On Unit testing. 53) When to use test doubles?
- 57. Answer: Model-View-Controller pattern separates data, UI and logic in different pieces of code, the controller populates data ad pass it to the view for the user. 54) Explain MVC
- 58. Answer: Reactive interface, faster integration, concern separation, modular client server independent. 55) Which are the MVC benefits?
- 59. Answer: template, templateUrl, selector, styles, stylesUrls, animation, interpolation, inputs, outputs, providers. 56) Which are some component decorator options?
- 60. THANKS! I am Luis Espino I am here because I love to spread knowledge. I wish this info will help you. You can find me at @espino316. Checkout my projects at luis.espino.info