Wipro Junior Frontend Developer Interview Questions and Answers

Dependency Injection is a design pattern in which a class receives its dependencies from external sources rather than creating them itself.

• Allows for easier testing by injecting mock dependencies

• Promotes reusability and modularity by decoupling components

• Reduces code duplication by centralizing dependency creation

• Example: Angular uses Dependency Injection to provide services to components

Routing is the process of navigating between different pages or views in a web application.

• Routing allows users to move between different parts of a web application without reloading the entire page

• It is implemented using a router module in Angular, which maps URLs to components

• Routes can have parameters that can be passed to components for dynamic content

• Routing can be used to create single-page applications (SPAs) wh

Debugger in JavaScript is used for pausing the execution of code to inspect variables, check the flow of the program, and debug errors.

• Debugger helps in identifying and fixing bugs in the code.

• It allows developers to step through code line by line to understand the flow of execution.

• Developers can inspect variables and their values at different points in the code.

• By setting breakpoints, developers can pause the code at...read more

CORS error occurs when a web application makes a request to a different domain than the one it originated from.

• CORS stands for Cross-Origin Resource Sharing

• It is a security feature implemented by browsers to prevent unauthorized access to resources on a different domain

• CORS error can be resolved by configuring the server to include the appropriate CORS headers in the response

• Common CORS error messages include 'Access-C...read more

Promises in JavaScript are objects representing the eventual completion or failure of an asynchronous operation.

• Promises are used to handle asynchronous operations in JavaScript.

• They can be in one of three states: pending, fulfilled, or rejected.

• Promises can be chained using .then() method to handle success and failure cases.

• Promises help in avoiding callback hell and writing cleaner asynchronous code.

Directives are used to add behavior to existing DOM elements, while components are used to create new custom elements.

• Directives are used to manipulate the behavior of existing DOM elements, such as changing their appearance or adding event listeners.

• Components are used to create custom elements with their own templates, styles, and behavior.

• Directives can be structural (like ngIf and ngFor) or attribute-based (like ng...read more

Hoisting is a JavaScript mechanism where variable and function declarations are moved to the top of their containing scope during compilation.

• Variable and function declarations are hoisted to the top of their scope, regardless of where they are declared in the code.

• Only the declarations are hoisted, not the initializations.

• Function declarations are hoisted before variable declarations.

Design patterns are reusable solutions to common problems in software design.

• Design patterns help in creating maintainable, scalable, and efficient code.

• They provide a common language for developers to communicate about solutions to recurring problems.

• Examples of design patterns include Singleton, Factory, Observer, and Strategy patterns.

ReplaySubject is a type of Subject in RxJS that records multiple values and replays them to new subscribers.

• ReplaySubject is a type of Subject in RxJS

• It records multiple values and replays them to new subscribers

• It has a buffer size that determines how many values to replay

Time queue in API refers to managing requests in a sequential order.

• Time queue ensures that API requests are processed in the order they are received.

• It helps in preventing overload on the server by limiting the number of concurrent requests.

• Examples include using promises or async/await in JavaScript to handle API calls sequentially.