PD1 Lightning Components 3

Question 1

In LWC, which event option must be set to `true` for a custom event to cross shadow DOM boundaries to an ancestor component?

Accepted Answer

Both bubbles: true and composed: true

Answer

For a custom event to traverse both the shadow DOM boundary and bubble up the DOM tree, both bubbles and composed must be set to true.

Question 2

Which Aura component attribute allows you to define regions where parent components can inject markup?

Accepted Answer

<aura:slot>

Answer

(similar to in LWC) defines placeholder regions in an Aura component that parent components can fill with markup.

Question 3

When using @wire with a Salesforce Apex method in LWC, what are the two properties available on the wired result object?

Accepted Answer

data and error

Answer

A @wire result object exposes data (the successful response) and error (any error that occurred), following LWC's standard wire adapter pattern.

Question 4

In LWC, how do you reference a static resource named 'myResource' in JavaScript?

Accepted Answer

import myResource from '@salesforce/resourceUrl/myResource';

Answer

The @salesforce/resourceUrl scoped module import is used to reference static resources in LWC JavaScript files.

Question 5

Which method is used in LWC to query a single element within the component's template?

Accepted Answer

this.template.querySelector()

Answer

In LWC, this.template.querySelector() scopes the query to the component's shadow DOM, preventing access to elements outside the component.

(PD1) Salesforce Certified Platform Developer 1 Practice Test