Svelte.js Interview Questions and Answers
Intermediate / 1 to 5 years experienced level questions & answers
Ques 1. Explain the concept of reactivity in Svelte.
Reactivity in Svelte refers to the automatic updating of the DOM when the state of a variable changes. Svelte achieves this without the need for a virtual DOM.
Ques 2. Differentiate between Svelte and other front-end frameworks like React or Vue.
Svelte compiles components to highly optimized JavaScript at build time, resulting in smaller bundle sizes and improved performance compared to traditional virtual DOM-based frameworks like React or Vue.
Ques 3. Explain the Svelte component lifecycle.
Svelte components have a simplified lifecycle compared to other frameworks. They do not have lifecycle methods like 'componentDidMount' or 'componentWillUnmount'. Instead, Svelte components have 'onMount' and 'onDestroy' lifecycle functions.
Ques 4. Explain the concept of stores in Svelte.
Stores in Svelte are reactive containers for state management. They allow sharing state between components and automatically update when the state changes.
Ques 5. How does Svelte handle animations?
Svelte has built-in support for animations. You can use the 'animate:' directive to create smooth transitions and animations between state changes in components.
Ques 6. How can you pass data between parent and child components in Svelte?
Data can be passed from parent to child components in Svelte using props. The parent component can bind a variable to a child component property, ensuring updates are reflected in the child.
Ques 7. What are Svelte transitions, and how do you use them?
Svelte transitions enable smooth animations during element insertion, removal, or state changes. You can use 'in:' and 'out:' directives to specify transition effects.
Ques 8. Explain the role of the 'key' attribute in Svelte's each block.
The 'key' attribute in Svelte's each block is used to uniquely identify elements during iteration. It helps Svelte efficiently update the DOM when the list changes.
Ques 9. What is the purpose of the 'context' API in Svelte?
The 'context' API in Svelte allows components to communicate indirectly by sharing state with their descendants. It's useful for avoiding prop drilling.
Ques 10. What is the purpose of the 'use:' directive in Svelte?
The 'use:' directive in Svelte is used to apply actions to DOM elements. Actions are functions that can perform side effects, like animating or interacting with the DOM.
Ques 11. How can you handle route parameters in Svelte?
Svelte allows you to handle route parameters using the '$route' store. You can subscribe to changes in route parameters and update your component's state accordingly.
Ques 12. How does Svelte handle code splitting?
Svelte supports automatic code splitting, meaning that only the components used in a specific route or part of your application are included in the final bundle.
Ques 13. How can you handle side effects in Svelte?
Side effects in Svelte can be handled using lifecycle functions like 'onMount' and 'onDestroy'. These functions are suitable for performing actions when a component is mounted or unmounted.
Ques 14. What are slots in Svelte, and how do you use them?
Slots in Svelte allow you to create reusable components with placeholders for content. They provide a way to pass content into a component from its parent.
Ques 15. What is the purpose of the 'slot' attribute in Svelte?
The 'slot' attribute in Svelte is used to define named slots in a component. It allows the parent component to provide content for specific areas of the child component.
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