Lightning framework is very powerful and tightly coupled with Salesforce resources and Apex. You can use aura reference “$A” to get values from global value providers like Label, Localization, User Details etc.

53. How to get a System Label value in Aura Component?

To get system label in aura component, user $A.get() method. Like $A.get(“$Label.namespace.label_api_name”);

Example - $A.get(“$Label.c.header_name”);

54. How to get current signed in user’s id?

$A.get("$SObjectType.CurrentUser.Id");

55. How to get browser information in component?

Use $Browser global value provider to return information about the hardware and operating system of the browser accessing the application. Example:

var device = $A.get("$Browser.formFactor");
alert("You are using a " + device);

56. How to get current user’s timezone?

$A.get("$Locale.timezone");

57. How to reference a static resource from JavaScript?

Use $Resource global value provider in JavaScript to refer a static resource file. Example:

$A.get('$Resource.ResourceName’) + '/assets/images/avatar1.jpg';

58. How to set attribute value from JavaScript?

Use component.set() method to set an attribute value in JavaScript. Example:

<aura:attribute name=“greeting” type=“String” />

In JavaScript you can set attribute value like below:

component.set(“v.greeting”, “Hello World”);

59. How to get attribute value in JavaScript?

Use component.get() method to get an attribute value in JavaScript. Example:

<aura:attribute name=“greeting” type=“String” />

In JavaScript you can get attribute value like below:

var gettingValue = component.get(“v.greeting”);

60. What is component.find() method and why is it being used?

component.find() method is used to find an element from component markup using aura:id. This method return complete element and can be used to set attribute values of element or performing any other operations like changing CSS classes etc.

<lightning:input aura:id=“nameInput”  value=“Manish”/>

In JavaScript, you can dynamically change the value attribute of above lightning:input-

var inputElement = component.find(“nameInput”);
inputElement.set(“v.value”, “SFDCFacts”);

61. Why we use component.getEvent() method?

component.getEvent() method is used to get a reference of registered component event in component markup. Once the event is retrieved, same can be fired from JavaScript. Example:

<aura:registerEvent name=“onTileSelect” type=“c:TileSelectEvent”/>

You can get above component event in controller:

var tileSelectEvent = component.getEvent(“onTileSelect”);
tileSelectEvent.fire();//fire the event

Read Also:

• • Interview Questions – Lightning Framework – Part 6 – Conditional Markup, Iteration & CSS
  • Interview Questions – Lightning Framework – Part 8 – Lightning Locker, Aura Methods
  • Access Attribute And Markup In Controller
  • Handling Browser Events And Controller File