This must be a a very simple question, but may be I'm doing it wrong.

I wanted to set default aura:attribute value to null on lightning component as below.


<aura:attribute name="selectedObj" type="Object" default="null"/>

but this gives me selectedValue as a String, and not comparing with null in lightning javascript controller/helper code.

let selectedObj = component.get('v.selectedObj');

console.log('selectedObj: '+(selectedObj===null) +' string comparison: '+(selectedObj==='null'));
component.set('v.selectedObj', null);
console.log('selectedObj: '+(component.get('v.selectedObj')==null)+' string comparison: '+(component.get('v.selectedObj')=='null'));


selectedObj: false string comparison: true 
selectedObj: true string comparison: false

Therefore I had to set null value explicitly in javascript controller at the initialization. e.g.

component.set('v.selectedObj', null);

Is this the correct approach to set null in javascript? are there any better alternatives to set default null value for aura:attribute?


1 Answer 1


Don't define a default attribute. This causes the attribute to default to null.


<aura:attribute name="selectedObj" type="Object" />
  • 1
    too easy, thanks! Commented Oct 15, 2019 at 2:26
  • Yeah, I was wondering if it was bad to have such a short answer... But I couldn't think of anything else useful to add! Commented Oct 15, 2019 at 2:26

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