UST Front end Developer Interview Questions and Answers

Promises 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() to handle success and .catch() to handle errors.

• Example: const myPromise = new Promise((resolve, reject) => { ... });

Box model in CSS refers to the way elements are rendered in a web page. CSS preprocessors like SASS or LESS help streamline CSS development.

• Box model in CSS includes content, padding, border, and margin.

• CSS preprocessors like SASS or LESS allow for variables, nesting, and mixins to be used in CSS.

• Example: box-sizing: border-box; in CSS changes the box model to include padding and border in the element's total width and

Micro Frontend architecture is an approach to building front-end applications by breaking them down into smaller, independently deployable units.

• Allows different teams to work on separate parts of the application

• Each micro frontend can be developed using different technologies

• Enables incremental upgrades and updates without affecting the entire application

• Can improve performance by loading only the necessary components

• ...read more

Pure pipes in Angular are stateless and do not change the input data, while impure pipes can have side effects and change the input data.

• Pure pipes are used for simple transformations like formatting dates or numbers.

• Impure pipes are used for more complex transformations that require state or side effects.

• Pure pipes are faster and more efficient as they only run when a pure change to the input data is detected.

• Impure p...read more

Singleton services can be made multiton by maintaining a map of instances with unique keys.

• Create a map to store instances with unique keys

• Use a factory method to retrieve instances based on keys

• Ensure that only one instance is created per key

Dependency injection is a design pattern where components are given their dependencies rather than creating them internally.

• Allows for easier testing by injecting mock dependencies

• Promotes loose coupling between components

• Improves code reusability and maintainability

• Examples: AngularJS, Spring Framework