Top 10 Aura Components Interview Questions
Have a look at these Top 10 Aura Components Interview Questions and I can guarantee that you will excel in your interview.
These are the questions that you need to check before you give an interview on Aura Components (Lightning Components).
What is <aura:method /> tag used for?
When we want to invoke a JavaScript method in the child component from the parent component then we will use <aura:method /> tag in Aura Components.
In case you are interested in checking out a working example you can check this
Difference between Aura Components and LWC?
LWC components are 50% faster than Aura Components. LWC Components uses the concept of Custom Elements and that's not the case with Aura Components. LWC is built on Web Components architecture and that's not the case with Aura Components. With LWC we work with native JavaScript and there is no file conversion or file parsing that happens, however, that's not the case with Aura Components.
How can you send data from parent to child and from child to parent in Aura Components?
Data can be sent from parent to child components via attributes whereas when we want to send info from child to parent we need to use Component Events.
Component event is the exact opposite of <aura:method /> tag.
What are the files that get created when an Aura Component is created?
When we create an Aura Component, 8 files will be generated and this is called resource bundle. These files are Component File (.cmp file), Controller File (.js file), Helper File (.js file), Style File (.css file), Documentation File (.auradoc file), Renderer File (.js file), Design File (.design file), SVG File (s.vg file).
What's the purpose of `implements` in Aura Components?
When we use this attribute on the tag <aura:component> the component gets the special capabilities such that it can be placed on a record page, it can grab the record id from the URL, it can be used in communities, etc.
I have a component (say component A) that has a neighbor (say Component B), both these components are siblings. How can I send data from Component A to Component B?
We can use Application Events to send info from Component A to Component B. This is typically used when we want to share data between components that are not in the hierarchy.
What is an unbound expression in Aura Components?
When we send data from parent component to child component and modify it in the child component the updated (or mutated) data will be pushed back to the parent component too, because of the concept of reactivity. If you don't want the behavior and wish to have different values to attributes in different components then we will use the unbound expression in Aura Components.
How can we embed Aura Component in a Visualforce page?
We need to use the concept of Lightning Out and expose the Aura Components in the Lightning App using the tag <aura:dependency /> and in turn embed the Lightning App in the Visualforce page. This is the route we need to take to embed the Aura Component in Visualforce pages.
Can we expose an Aura Component (and Visualforce page) in LWC?
No, however, the vice-versa is possible we can expose an LWC in Aura Components.
What's the use of having both Controller and Helper files in Aura Components?
When we have the same instance of a tag used multiple times. The helper.js file will be downloaded only once and it will be shared by the other instances of the same component. This increases the performance and reduces the usage of bandwidth.
I have shared some more information regarding this here.
Just check these questions and you will be in safe hands!