Senior UI Engineer Interview Questions and Answers

List virtualisation optimises rendering by only rendering items that are currently visible on the screen.

• Use virtual scrolling to render only the visible items in a list

• Implement windowing techniques to dynamically load and unload items as the user scrolls

• Utilize libraries like React Virtualized or Angular CDK Virtual Scroll for efficient list rendering

Pseudo elements are used to style specific parts of an element, while pseudo classes are used to style an element based on its state or position.

• Pseudo elements are denoted by :: before the element name, like ::before or ::after

• Pseudo classes are denoted by a single colon before the class name, like :hover or :active

• Pseudo elements are used to style parts of an element that do not exist in the DOM, like adding content before or after an element

• Pseudo classes are used to style...read more

Inline elements do not start on a new line and only take up as much width as necessary, while block elements start on a new line and take up the full width available.

• Inline elements do not force a new line to start and only take up as much width as necessary (e.g. <span>, <a>, <strong>).

• Block elements always start on a new line and take up the full width available (e.g. <div>, <p>, <h1>).

• Inline elements can have margin and padding applied horizontally but not vertically.

• Block...read more

Primitives in JS are data types that are not objects and are immutable.

• Types of primitives in JS include string, number, boolean, null, undefined, and symbol.

• Primitives are passed by value, not by reference.

• Examples: 'hello' (string), 42 (number), true (boolean), null, undefined, Symbol('foo')

Directives in AngularJS allow you to create custom HTML tags and attributes that extend the functionality of HTML.

• Directives are markers on a DOM element that tell AngularJS to attach a specified behavior to that DOM element.

• They can be used to create reusable components, manipulate the DOM, and add interactivity to an application.

• Examples of directives include ng-model, ng-show, ng-hide, ng-repeat, and custom directives created by the developer.