Capgemini Interview Questions for Salesforce Developer | 4+ YOE | May 2024

Summary

This video provides an in-depth look at key Salesforce concepts, particularly around Lightning Web Components (LWC) and Apex. The presenter answers interview questions on topics such as using wire decorators for fetching data, differences between wire and connectedCallback, handling form submissions with duplicate checks, user-specific component visibility, and managing duplicate records. The explanations are paired with real-world examples and code snippets, making it an insightful guide for developers preparing for Salesforce-related interviews. The session also touches on the use of wrapper classes and efficient querying techniques for managing Salesforce data.

Takeaways

• 😀 The wire decorator in LWC is used to fetch data from Salesforce via Apex, especially for displaying related records in components like a lightning data table.
• 😀 Wire versus connectedCallback: wire is a decorator for reactive data binding, while connectedCallback is a lifecycle hook used for component initialization.
• 😀 The difference between wire and connectedCallback includes their order of execution, with wire executing first, followed by connectedCallback.
• 😀 A Lightning Web Component (LWC) form can be used to capture data such as name and email, and on submit, Apex is used to check if a contact with the same email already exists before creating a new one.
• 😀 To handle duplicate records in Salesforce, Apex is used to query and prevent the creation of duplicate contacts by checking existing records.
• 😀 Custom metadata and user profiles can be used to conditionally display an LWC component to specific users based on criteria like their email or profile settings.
• 😀 Custom settings, particularly hierarchical custom settings, are a recommended solution for controlling component visibility across user profiles.
• 😀 Wrapper classes in Salesforce allow for returning multiple different types of data (e.g., lists, strings, accounts) from a function, providing flexibility in return types.
• 😀 A Salesforce query can be written to fetch all accounts with related contacts by using a subquery on the contact object.
• 😀 For cleaning up duplicate records, a script can use a map to track unique account names and delete records with duplicated names, leaving only the original record.

Q & A

What is the purpose of the wire decorator in Salesforce LWC?

The wire decorator in Salesforce LWC is used to fetch data from Salesforce, typically via Apex methods, and bind that data to the component's properties. This allows for automatic updates of the component when the data changes.

Can you explain the difference between wire and connectedCallback in LWC?

Wire is a decorator that allows for the automatic fetching and binding of data from Salesforce. It executes first in the component lifecycle. On the other hand, connectedCallback is a lifecycle hook that runs when the component is inserted into the DOM, usually after wire executes, and is used for initialization tasks that don't require data fetching.

How would you handle duplicate contacts in LWC based on email submission?

To handle duplicate contacts, you can use an HTML form with name and email fields. Upon submission, the form values are captured using JavaScript's querySelector, and an Apex method is called to check if a contact already exists based on the email. If the email is found, an error is returned; otherwise, a new contact is created.

How can we conditionally show an LWC component to different user profiles?

One method is to use custom metadata to store the emails of the users for whom the LWC component should be visible. Another way is to use a checkbox on the user record, marking users who should see the component. These conditions can be handled using the <template if:true> directive in LWC.

What is the purpose of wrapper classes in Salesforce?

Wrapper classes in Salesforce allow a method to return multiple types of data. This is useful when the return type can't be determined beforehand, allowing for flexibility in returning various objects, like lists of different types of records or mixed data types.

How can you query accounts that have related contacts in Salesforce?

To query accounts with related contacts, you can use a SOQL query like: SELECT Id FROM Account WHERE Id IN (SELECT AccountId FROM Contact). This retrieves all accounts that have associated contacts.

What is the approach to deleting duplicate accounts in Salesforce based on account names?

To delete duplicate accounts, first, a map is created to store unique account names and IDs. After querying all accounts, the script checks if the account name already exists in the map. If not, the account is added to the map. Duplicate accounts are then deleted by querying for accounts that have the same name but different IDs, excluding the unique ones.

How does the wire decorator ensure real-time data updates in LWC?

The wire decorator ensures real-time updates by automatically re-running when its reactive properties change. This means any change to the data source, like a change in Salesforce, will trigger an update in the LWC component.

When should you use connectedCallback instead of wire in LWC?

connectedCallback should be used when you need to perform actions during the component's lifecycle, such as initializing values or executing logic that doesn’t require fetching data from Salesforce. If data fetching is necessary, wire is the better choice.

What is the role of Apex in an LWC form submission for creating or checking contacts?

Apex is used in LWC to perform server-side logic such as querying Salesforce for existing contacts by email. If a duplicate contact exists, the Apex method returns an error message. If no duplicates are found, it creates a new contact record.