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chrish1-Visitor
1-Visitor
April 18, 2016
Solved

How can I set a defined variable to NULL?

  • April 18, 2016
  • 3 replies
  • 2155 views

I need to be able to reset a variable (specifically a UserSession variable/property) to NULL so that the behavior of my mashup is predictable.

I've tried:

newObject.username = NULL;

But this syntax throws a runtime error that "NULL" isn't defined.

Thanks for the help.

Best answer by chrish

Stefan / Carlos, I actually figured this one out with a little trial and error. The keyword is actually "null" (all lower case). You can actually set a property to "null". I did it successfully; to the point that a Mashup Validate widget correctly evaluated an expression UserName=null as TRUE.

HOWEVER!!!  The exception to this is SESSION properties. Once set; they will not reset to null without restarting browser (session). If you set them to "null"; they are simply set to "" (which is useful knowledge in it's own way). Hope this helps!  It certainly did me.

3 replies

S
StefanBode12-Amethyst
12-Amethyst
April 19, 2016

I'm not sure, but I assume the "NULL" must be "undefined". Have seen this in some JAVA scripts.

C
CarlesColl1-Visitor
1-Visitor
April 19, 2016

I think it's not possible, I usually face this need too, but there's no way to "undefine" or set to null to an already set property.

C
chrish1-VisitorAuthorAnswer
1-Visitor
April 27, 2016

Stefan / Carlos, I actually figured this one out with a little trial and error. The keyword is actually "null" (all lower case). You can actually set a property to "null". I did it successfully; to the point that a Mashup Validate widget correctly evaluated an expression UserName=null as TRUE.

HOWEVER!!!  The exception to this is SESSION properties. Once set; they will not reset to null without restarting browser (session). If you set them to "null"; they are simply set to "" (which is useful knowledge in it's own way). Hope this helps!  It certainly did me.

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