10+ Wipro Interview Questions and Answers

Lazy loading is a technique used to defer loading of non-essential resources until they are actually needed.

• Lazy loading helps improve the initial loading time of a web application by only loading essential resources upfront.

• In Angular, lazy loading is achieved by creating separate modules for different parts of the application and loading them on demand.

• Lazy loading can be implemented using the loadChildren property in the route configuration of Angular.

• Lazy loading is commo...read more

Constructor is used to initialize class properties, NgOnInit() is a lifecycle hook used to perform initialization after Angular has initialized the component.

• Constructor is a TypeScript feature used to create and initialize class properties.

• NgOnInit() is an Angular lifecycle hook that is called after Angular has initialized the component.

• Constructor is called before NgOnInit() during component initialization.

• Example: Constructor is used to inject services, NgOnInit() is used ...read more

A pipe in Angular is used to transform data before displaying it in the template.

• Pipes are used in templates to format data before displaying it to the user

• There are built-in pipes like DatePipe, UpperCasePipe, LowerCasePipe, etc.

• Custom pipes can also be created by implementing the PipeTransform interface

• Pipes can be chained together to perform multiple transformations on the data

Use JavaScript to remove duplicate elements from an array of strings.

• Create a new Set from the array to automatically remove duplicates

• Convert the Set back to an array to get the final result

Two-way binding is a feature in Angular that allows automatic synchronization of data between the model and the view.

• Two-way binding allows changes in the model to be reflected in the view and vice versa

• It simplifies the process of updating the UI based on user input or changes in the data model

• Example: Using ngModel directive in Angular forms to bind input fields to model properties

Observable is a stream that allows multiple values over time, while Promise is a single value that resolves or rejects.

• Observable can handle multiple values over time, while Promise can only handle a single value.

• Observable is lazy, meaning it won't execute until it is subscribed to, while Promise is eager and executes immediately.

• Observable is cancellable, allowing you to unsubscribe, while Promise is not cancellable once it is settled.

• Observable provides operators for trans...read more

Array methods in JavaScript and their differences

• forEach() - executes a provided function once for each array element

• map() - creates a new array with the results of calling a provided function on every element

• filter() - creates a new array with all elements that pass the test implemented by the provided function

• reduce() - applies a function against an accumulator and each element in the array to reduce it to a single value

• find() - returns the first element in the array that s...read more

Data binding is the automatic synchronization of data between the model and view components in an application.

• Data binding allows for the seamless updating of data in the model to be reflected in the view and vice versa.

• There are two-way data binding and one-way data binding.

• Two-way data binding updates the model and view simultaneously, while one-way data binding updates in one direction only.

• Example: In Angular, using interpolation {{ }} or property binding [ ] for one-way ...read more

Lazy loading is a technique used to defer loading of non-essential resources until they are actually needed.

• Lazy loading helps improve performance by only loading resources when they are required.

• In Angular, lazy loading is commonly used for loading modules on demand rather than loading everything upfront.

• Lazy loading can be implemented using Angular's RouterModule and loadChildren feature.

Sort array without using methods

• Iterate through the array and compare each element with the rest to find the correct position

• Swap elements if necessary to sort the array in ascending order

• Repeat the process until the array is fully sorted

RxJS operators are functions used to manipulate and work with streams of data in reactive programming.

• RxJS operators are used to transform, filter, combine, and handle errors in data streams.

• Examples of RxJS operators include map, filter, mergeMap, switchMap, catchError, and debounceTime.

• Operators are used in combination with Observables to create powerful data processing pipelines.

• Understanding and mastering RxJS operators is essential for efficient data handling in Angular ...read more

ngClass is used to conditionally apply CSS classes to an element in Angular.

• Use ngClass directive in the template with an object or array of classes and conditions

• Classes are applied when the condition is true, and removed when false

• Example:

Angular interceptors are a way to intercept HTTP requests and responses to perform operations like logging, modifying requests, or handling errors.

• Interceptors can be used to modify outgoing requests or incoming responses.

• They can be used for tasks like adding headers, logging requests, handling errors, or transforming data.

• Interceptors are implemented as services that implement the HttpInterceptor interface.

• Multiple interceptors can be chained together to perform different t...read more

Angular provides a robust framework for building dynamic web applications with features like two-way data binding, dependency injection, and modular architecture.

• Angular offers a powerful toolset for creating single-page applications (SPAs) with a clean and organized code structure.

• It provides built-in features like routing, forms handling, and HTTP client for seamless development.

• Angular's two-way data binding simplifies the process of updating the UI based on changes in the...read more

Decorators are a design pattern in Angular that allows you to add behavior to classes, properties, or methods.

• Decorators are functions that are prefixed with @ symbol and are used to modify classes or class members.

• They are commonly used in Angular for metadata annotations, dependency injection, and more.

• Examples include @Component, @Injectable, @Input, @Output, etc.

Directives are markers on a DOM element that tell Angular to attach a specified behavior to that DOM element or transform the DOM element and its children.

• Directives are used to extend HTML with new attributes or elements.

• There are three types of directives in Angular: Component, Structural, and Attribute directives.

• Examples of directives include ngIf, ngFor, ngStyle, and custom directives created by developers.

Reverse a string without using built-in methods

• Create an empty string to store the reversed string

• Iterate through the input string from the last character to the first

• Append each character to the empty string to reverse the input string

The entry point of Angular is typically the main.ts file.

• Main.ts file is the first file that is executed when an Angular application is started.

• It bootstraps the AppModule, which is the root module of the application.

• Main.ts file also imports other necessary modules and components required for the application to run.