Vue.js Interview Questions

Vue is a JavaScript framework used to create connected interfaces. Evan invented it, and he, along with the other active core team members, continues to maintain it. Vue.js is in charge of the view layer of an application. Vue.js Interview Questions the primary purpose of Vue.js interview questions is to assess the criticacandidate's l thinking skills and local knowledge; therefore, these questions have been classified depending on the difficulty level, that is, primary, intermediate, or advanced questions. 

In this Blog, we have included the most recent and frequently asked Vue.js Interview Questions and Answers that have been further categorized as per the criteria mentioned above.

• Basic Vue.js Interview Questions for Freshers
• Intermediate Vue.js Interview Questions
• Advanced Vue.js Interview Questions for Experienced
• Tips
• FAQs

Most frequently asked Vue.js Interview Questions What are the significant features of Vue.JS? What are the filters in vue.js? Mention some of the alternatives to vue.js. Why is Vue.js so fast? Vue consists of how many components? What are the advantages of utilizing Vue.js Mixins? What are the array detection non-mutation methods in Vue.js? What is vuex?  What is the $parent property in Vue.js?

Basic Vue.js Interview Questions for Freshers

Q1) What is Vue.js?

Ans: Vue.js is a javascript framework used to develop the interactive interface. It's a progressive framework. Fast DOM rendering, reactive state management, tools, client-side routing, and server-side rendering are all higher-level problems that Vue addresses.

Q2) Who is the founder of Vue.js?

Ans: Evans invented Vue. JS. He and his team members maintain it.

Q3) Why is Vue.js called a progressive framework?

Ans: Vue.js is called a progressive framework because it is dynamic.

Q4) Can we create a custom filter in Vue.js?

Ans: Yes, a custom filter can be created in Vue.js.

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Q5) What are the significant features of Vue.JS?

Ans: Some of the significant features of Vue.js are:

• Components
• Virtual DOM
• Lightweight
• Routing
• Templates

Q6) What are the filters in vue.js?

Ans: A filter is a JS function that assists in changing the output of data to the browser.

Q7) Mention some of the array change detection and mutation method in Vue.js

Ans: Some of the array change detection and mutation method in vue.js are:

• push()
• pop()
• shift()
• slice()
• sort() and so on.

Q8) Is vue.js supported by most browsers?

Ans: Yes, the majority of browsers support vue.js.

Q9) Does vue.js provide two-way communications?

Ans: Yes, it provides two-way communication.

Q10) Name some of the popular websites that use vue.js.

Ans: Some favorite websites that use Vue.js are:

• Grammarly
• Netflix
• Xiaomi
• Facebook
• Trivago
• Codeship
• Alibaba

Q11) Mention some of the alternatives to vue.js.

Ans: Some of the alternatives available for vue.js include:

• Angular
• React
• Bootstrap
• jQuery

Q12) What is the use of the 'const' keyword in Vue.js?

Ans: The 'const' keyword helps create constants.

Q13) What is the use of Vue-router?

Ans: Vue router makes the connection between browser URl and Vues.

Q14) Why is Vue.js so fast?

Ans: Vue.js operates quicker than other Javascript frameworks because of the use of a lightweight virtual DOM.

Q15) Mention one advantage of using mixins in Vue.js.

Ans: The foremost advantage of using mixins in Vue.JS is that they offer flexibility in the distribution of reusable features.

Q16) Are filters reusable in Vue?

Ans: Yes, the filters can be reused in Vue.

Q17) Vue consists of how many components?

Ans: Vue comprises three components which are mentioned below:

• Templates
• Styles
• JavaScript 

Q18) How can one add extra features to the application in Vue.js?

Ans: Vue-Plugins can be used to add extra features to the application in Vue.js.

Q19) Mention some of the advantages of using Vue.js.

Ans: Vue.js provides numerous benefits to users. Some of them include the following:

• Easy integrations
• Reliability 
• User-friendly
• Improved performance
• Easy to grasp

Q20) List out some of the conditional directives in Vue.js.

Ans: Some of the conditional directives included in Vue.js are mentioned below:

• V-if
• V-else
• V-else-if
• V-show

 

Intermediate Vue.js Interview Questions

Q21) What are the advantages of utilizing Vue.js Mixins?

Ans: To flexibly distribute reusable features, the developers in Vue.js use mixins. There are numerous component options in mixins. They are held in one location, enabling all the components to be benefitted simultaneously.

Q22) What is the primary purpose of using virtual DOM in Vue.js?

Ans: The primary goal of the virtual DOM is to speed up and improve the effectiveness of DOM manipulation. When your DOM contains many nodes, it becomes essential. In this situation, upgrading these nodes is costly for resource- and processing-intensive activity. Here, virtual DOM enters the picture and substantially speeds up JavaScript objects. To increase efficiency, Vue.js automatically groups DOM updates into bunches.

Q23) Why is it necessary for the component data to be a function?

Ans: The component data must be a function rather than just providing the object as a copy of the returned data object required for each instance. Or else data change in one component instance will impact data in all other component instances.

Q24) What are the array detection non-mutation methods in Vue.js?

Ans: The methods in Vue.js that consistently produce a new array instead of changing the original array are known as array detection non-mutation methods.

A list of the non-mutation methods are:

• slice()
• filter()
• concat()

Q25) In vue router, what are navigation guards?

Ans: By deviating from or canceling navigations, vue-navigation routers protect navigations.

The following is a list of the three methods that can be plugged into router navigations:

• Per-route
• In-component
• Global

Q26) What is the difference between one-way and two-way data binding?

Ans: The application UI part does not automatically update in one-way data binding. A custom code must be entered to ensure that updates are made after each change. Moreover, one-way data binding involves the usage of the v-bind Directive. 

On the contrary, two-way data binding can automatically update the application's UI, considering that the data model is updated. The v-model Directive is used in the case of two-way data binding.

Q27) What are the primary uses of filters in Vue.js?

Ans: The main functions performed by filters in vue.js are:

• They are generally used to filter data at the DOM level. This is done so that data still intact in storage but presented in the specified way can be received.
• They are used to enhance the presentation of the view layer.
• Moreover, filters are reusable.
• Filters make it more convenient to format data at the view level.

Q28) Mention types of Directive available in Vue.js.

Ans: The following directives are available in Vue js:

• Empty Directives
• Custom Directives
• General Directives
• Literal Directives

Q29) What is a watcher in vue.js?

Ans: A watcher in vue.js refers to a unique feature that assists in observing changes in data while applying various operations.

Q30) What makes Vue superior to Angular?

Ans: Angular helps in building enterprise-based applications owing to its extensive built-in functionalities and community support. However, Vue is a technically sound framework that assists in building user interfaces and solving various challenging issues.

Q31) What is the difference between v-if and v-show directives?

Ans: The most common differences between v-show and v-if directives are given below: 

• The v-if Directive is used to present the element to the DOM only if the expression succeeds, whereas the v-show Directive is used to present all elements to the DOM and then uses the CSS display property to show or hide elements according to the expressions.
• V-if directives support v-else and v- else-if directives, whereas v-show directives don't support them.
• The v-if Directive adds or removes the DOM, due to which it has a higher cost, whereas the v-show Directive has a higher initial render cost.
• v-if Directive supports the tab, whereas the v-show Directive doesn't support it.

Q32) What is vuex? 

Ans: VueX is a state management pattern and library for the Vue.js application. It acts as a centralized store for all the various components in the Vue.js application. Vuex provides rules to ensure that the state can only be changed predictably. Vuex help by keeping all that data in one place and allowing access to modify all of these separate components.

Q33) What is the key in Vue.js?

Ans: Vue.js reuses DOM elements rather than producing a new one each time to show DOM elements more quickly. The key is a kind of flag that tells Vue, "if the data associated with this child component is moved somewhere else, then move the component along with it to preserve the changes that already exist."

Q34) What is $child property in Vue.js?

Ans: The $child property in Vue.js is identical to the $parent property, even though it's used to access the child instance.

Q35) Explain Vue.js reactivity and common issues when tracking changes.

Ans: Each of the properties specified in a Vue instance's data option is reactive, which means that once they change, the component is instantly updated and re-rendered.

During initialization, all such properties are transformed into getters and setters, enabling Vue to recognize when those properties are viewed or modified.

The following limitation may occur while creating the Vue app:

• Due to a JavaScript restriction, Vue cannot detect the addition or deletion of object properties; as a result, new root-level reactive properties must be added via the Vue. Set method.
• In a similar vein, Vue cannot recognize index-based array item modifications. Vue. the Set is required to be used

 

Advanced Vue.js Interview Questions for Experienced

Q36) What is a vue-loader?

Ans: Vue loader allows the creation of single file components in vue format as it is a webpack plugin. Single component files include three sections that are template, script, and style. The vue-loader module allows Webpack to extract and process each section using different loader modules, such as the SASS or SCSS loader makest, making creating an app using vue files simple.

Q37) What is a single file component?

Ans: A file with the. Vue extension, which includes a Vue component, is referred to as a single-file component. It is a single file that contains the component's template, logic, and styling. One script block, optional template and style blocks, and additional custom blocks are included.

You must configure Vue Loader to parse the file before using one (usually done as part of a webpack building pipeline). However, this also encourages using non-standard languages like HTML templating languages or Sass with pluggable pre-processors.

Q38) How to use a single-file component in Vue.js?

Ans: We must set up Vue Loader to parse the file to use a single-file component in Vue.js (It is done automatically as a part of a webpack building pipeline). Additionally, HTML templating languages and Sass with pluggable pre-processors are supported in addition to non-standard languages.

Q39) What are the problems solved by single file components in Vue.js?

Ans: To solve common issues in a JavaScript-driven application with a.vue extension, Vue.js uses Single File Components.

The following is a list of problems that Single File Components in Vue.js have resolved:

• Every component has a unique name according to global criteria.
• String templates need ugly slashes for multiline HTML and lack syntax highlighting.
• CSS not supported. It means that CSS is completely absent from the modularization of HTML and JavaScript.

Q40) Explain the life cycle of the Vue instance 

Ans: Lifecycle hooks are functions that every Vue instance runs through. Each vue has eight lifecycle hooks. An instance of js

• Before Create - This is the first lifecycle hook that is called when a Vue instance has been created.
• Created - It's called immediately after the 'Before creates' hook, but the Vue instance has already set initial properties, data, etc.
• Before mount - invoked right before the instance is mounted on the DOM. The template has been completed at this time.
• Mounted - This is the name given to the template once it has been filled with data and is fully functional.
• Before Updated - When any changes to data require the DOM to be changed, this method is called before the update.
• Updated - It's called after the DOM has been updated.
• Before destroys - It's a location where you can clean up your resources before terminating the Vue instance.
• Destroyed - This method is called when all Vue instances have been destroyed. It will be activated when you call the destruct method on an object in the code.

Q41) Why should arrow functions not be utilized when writing lifecycle hooks in Vue instances?

Ans:

Arrow function can't define a 'this' of their own as they are not independent. They are limited to the context of their parent function.

The keyword 'this' does not bind to the Vue instance when the arrow function (=>) is used in the Vue app, resulting in problems.

Hence, Make use of the regular declaration instead of the arrow function.

Q42) What are the most prominent features of styling?

Ans: Following is a list of the most prominent features of styling:

• The stylelint has more than 160 built-in rules to catch errors, apply limits and enforce stylistic conventions.
• It understands the latest CSS syntax, including custom properties and level 4 selectors.
• It extracts the embedded styles from HTML, markdown, and CSS-in-JS object & template literals.
• It is also used to parse CSS-like syntaxes like SCSS, Sass, Less, and SugarSS.
• It supports reusing community plugins and creating their plugins.

Q43) How does data flow between components in a Vue.js app?

Ans: Data is transferred from the parent component to the child components in Vue.js using a prop or a custom attribute. This unique attribute is converted into a property on the instance of the child component. The process is known as a one-way data flow.

The subordinate component is automatically updated after the parent component modifies a prop value. The child component can use an event to interact with the parent, although changing a property within a child component is not recommended. Unless it is an object or array, it does not also influence the parent component. The parent sets a handler to the event when the child component instance emits one, and data is returned to the parent.

Q44) What is the $parent property in Vue.js?

Ans: The $parent property in Vue.js connects a child to the parent instance. Identical to the $root property. Direct access is provided through the $parent property. However, it makes it difficult to test and debug the application. It is challenging to identify the source of the mutation.

Q45) What are some of Vue's most crucial directives?

Ans:

V-if adds or removes DOM elements

The v-model is used for two-way data bindings.

To iterate over items in an array or object, we can use the v-for function.

Similar to v-if, v-show displays and hides elements using the CSS display property rather than rendering every element to the DOM.

 

FAQs related to Vue.js Interview Questions

Q1) Is Vue.JS front end or back end?

Vue.js is a JavaScript front-end framework that assists in building user interfaces. It is used for the creation of single-page applications. Moreover, it enables the developers to establish reusable components and manage the state of applications. It functions in the browser and interacts with the users, updating the application based on their inputs. However, Vue.js could be more helpful in backend development.

Q2) What are Mixins in Vue?

Mixins refer to a versatile approach that offers a more convenient way of distributing functionalities for vue components. Mixin objects can comprise various component choices. 

When a component uses a mixin, all mixin options are 'mixed' into the component's own.

Q3) What is virtual DOM in Vue?

The virtual DOM is a collection of JavaScript objects that depict DOM nodes that should be presented on the page and maintained by Vue.js. These are often known as VNodes or virtual nodes.

The foremost aim of virtual DOM is to manipulate the DOM promptly. When an alteration is mandatory, the operations are carried out on the Virtual DOM instead of the Real DOM.

Q4) What is VueJS mainly used for?

Vue.js is mainly used for creating web interfaces and single-page applications.

Q5) Can we use react's JSX in Vue?

No, you can't use react's JSK transform as it differs from vue JSK change in Vue applications.

 

Tips Related to VueJs Interview

1. Be concise and assured: Any response you provide during the interview should be as concise as possible.

2. Give some real-world examples: Try to use examples from the real world when responding. This will demonstrate to the interviewer your familiarity with the subject

3. Pitch and tone: keep your voice down and do not get aggressive. You can better communicate your argument using a low voice and a calm tone.

4. Research the company: Study the organization. Adjust your responses to the needs of the business.

5. Do not rush to respond; instead, pay close attention. Take the time to carefully consider the interviewer's questions, then respond.

 

Conclusion

Veu.js is continuously gaining popularity as it features a dynamically flexible architecture that focuses on the declarative present and component composition. It is used in the Information Technology and Services industry.

Listed are the 50 most common Vue.js Interview Questions and Answers, which will help you prepare and perform well. You can make a good impression on your potential employers by practicing and preparing. Best of luck!