Lightning Web Components

Question 1

What happens if you try to directly modify an object passed from a parent to a child?

Answer 1

An invalid mutation error is thrown.

Question 2

True or false: bound properties in {} can contain spaces.

Answer 2

False.

Question 3

What is the easiest way to work with Salesforce data in an LWC?

Answer 3

Use base Lightning components built on the Lightning Data Service (LDS).

Question 4

Which property of an event includes any sent data?

Answer 4

detail

Question 5

What is the syntax for loading the account object into a variable named ACCOUNT_OBJECT?

Answer 5

import ACCOUNT_OBJECT from “@salesforce/schema/Account”;

Question 6

Which two properties does a record page provide?

Answer 6

recordId and objectApiName

Question 7

How do you conditionally display content in an LWC?

Answer 7

Nest a template tag(s) with the lwcI:if={someProperty}. The lwc:elseif and lwc:else properties can also be used.

Question 8

How would you reference a component named viewSource in markup?

Answer 8

<c-view-source>

Question 9

How do you conditionally render markup in LWCs?

Answer 9

Use the lwc:if, lwc:elseif, and lwc:else attributes.

Question 10

What is the preferred, and easiest way to work with data in an LWC?

Answer 10

Lightning Data Service.

Question 11

In which directory are message channels stored?

Answer 11

force-app/main/default/messageChannels

Question 12

What is the proper syntax to import a method named myMethod from MyClass as MY_METHOD?

Answer 12

import MY_METHOD from ‘@salesforce/apex/MyClass.myMethod;

Question 13

What is a slot?

Answer 13

A placeholder for markup that a parent component passes into a component’s body.

Question 14

What is the file name format for a message channel?

Answer 14

messageChannelName.messageChannel-meta.xml

Question 15

Which method is used for dispatching events?

Answer 15

dispatchEvent()

Question 16

Which decorator exposes a field as a public property?

Answer 16

@api

Question 17

Which attribute is set to listen for an event on an input element?

Answer 17

onchange

Question 18

True or false: if you write a setter for a public property, you must also write a getter.

Answer 18

True.

Question 19

What would be the property syntax to import the method named queryAccounts that is marked @AuraEnabled and part of the class AccountListController into an LWC?

Answer 19

import queryAccounts from ‘@salesforce/apex/AccountListController.queryAccounts’;

Question 20

Which decorator marks a field as public?

Answer 20

@api

Question 21

True or false: an LWC folder and its file must have the same name, including capitalization and underscores.

Answer 21

True.

Question 22

True or false: all fields are reactive.

Answer 22

True.

Question 23

True or false: an LWC file/folder must begin with a lowercase letter.

Answer 23

True.

Question 24

How do you control when Apex method invocation occurs in an LWC?

Answer 24

Call the method imperatively.

Question 25

An array of Contact fields has been declared named FIELDS. What is the proper syntax to use these fields when wiring in to a property?

Answer 25

@wire(getRecord, {recordId: '$recordId', fields: FIELDS})

Question 26

What is the syntax to create a child component named myComponent and set a public property named myProperty to the value of a primitive named test?

Answer 26

``

Question 27

What decorator must be used to call an Apex method from an LWC?

Answer 27

@AuraEnabled

Question 28

What would the syntax be to define an iterator named it that iterates over an array named accounts?

Answer 28

`