Gallagher Interview Questions and Answers

Position property in CSS3 is used to set the position of an element relative to its parent or the viewport.

• The position property can take values like static, relative, absolute, fixed, and sticky.

• Static is the default value and elements are positioned according to the normal flow of the document.

• Relative positions the element relative to its normal position.

• Absolute positions the element relative to its nearest positioned ancestor.

• Fixed positions the element relative to the v...read more

Observables are a way to handle asynchronous data streams in Angular using RxJS library.

• Observables are similar to promises but can handle multiple values over time.

• They can be used for handling events, HTTP requests, and other asynchronous operations.

• Operators can be used to transform, filter, and combine observables.

• Subscriptions are used to listen to observables and receive data.

• Example: fetching data from an API using observables and subscribing to the response.

Closure is a function that has access to its parent scope even after the parent function has returned.

• Closure allows for private variables and functions in JavaScript.

• It is created when a function returns another function.

• The inner function has access to the outer function's variables and parameters.

• Example: function outer() { let x = 10; return function inner() { console.log(x); } }

• Example: const innerFunc = outer(); innerFunc(); // Output: 10

Prototype is a property of an object that allows adding new properties and methods to an object.

• Prototype is a blueprint for creating objects

• It allows inheritance by sharing properties and methods between objects

• Modifying the prototype affects all objects created from it

• Prototype chain allows accessing properties and methods of parent objects

• Example: Array.prototype includes() method

Pipe is a feature in Angular that allows transforming data before displaying it in the view.

• Pipes are used to format and manipulate data in Angular templates.

• They can be used to filter, sort, and transform data.

• Pipes can be chained together to perform multiple transformations.

• Angular provides built-in pipes like DatePipe, CurrencyPipe, and LowerCasePipe.

• Custom pipes can also be created to meet specific requirements.

Event loop is a continuous process that runs in the background and handles all the events in the application.

• Event loop continuously checks for new events in the event queue.

• It processes each event one by one in a synchronous manner.

• If an event takes too long to process, it can block the event loop and cause the application to freeze.

• Event loop can be controlled using setTimeout(), setInterval(), and setImmediate() methods.

• Node.js uses a single thread to handle all the events...read more

A directive is a component that adds behavior to an existing element or component in Angular.

• Directives are used to manipulate the DOM, add event listeners, and create reusable components.

• There are three types of directives in Angular: component, attribute, and structural.

• Examples of built-in directives in Angular include ngIf, ngFor, and ngStyle.

• Custom directives can be created using the @Directive decorator.

A component in Angular is a reusable piece of UI that consists of HTML, CSS, and TypeScript code.

• Components are the building blocks of Angular applications.

• Each component has its own logic and view.

• Components can be nested within other components.

• Components can communicate with each other using @Input and @Output decorators.

• Examples of components include a login form, a navigation menu, and a product list.