Lightning Aura Components Developer Guide

What Is the Lightning Component Framework?
Quick Start
Creating Components
Using Components
Communicating with Events
Communicating Across the DOM with Lightning Message Service
Creating Apps
Styling Apps
Developing Secure Code
Using JavaScript
Working with Salesforce Data
Testing Components with Lightning Testing Service
Debugging
Performance
Reference
Component Library
System Tag Reference
JavaScript API
$A namespace
Action
AuraLocalizationService
Component
Event
Util
addClass()
getBooleanValue()
hasClass()
isArray()
isEmpty()
isObject()
isUndefined()
isUndefinedOrNull()
removeClass()
toggleClass()
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isUndefined()

Checks if the object is undefined.

Signature

isUndefined(Object obj)

Parameters

obj
Type: Object
The object to check.

Returns

Type: Boolean
Returns true if the object is undefined, or false otherwise.