JSON return null in ColdFusion

Question

I want to return a null as a part of my JSON response

local.JSON = { "pwdstate" : null, "pwdconfirmstate" : null, "content" : "" };
...
framework.renderData().data( SerializeJSON(local.JSON) ).type( "rawjson" );

But I get an error that says Variable NULL is undefined.

How do I send back a null?

Note: Non-existence is not an option

Have you tried `"pwdstate" : javaCast( "null", "" )`? – rrk Mar 30 '20 at 03:19 — rrk, Mar 30 '20 at 03:19

score 2 · Accepted Answer · answered Mar 30 '20 at 11:31

The literal null expression was introduced in ColdFusion 2018. You still need to explicitly enabled it, either on server level (admin panel, Admin API) or on application level (this.enableNullSupport = true in Application.cfc).

You can work around it using javaCast("null", "") for all versions >= ColdFusion 7 and <= ColdFusion 2016.

JSON return null in ColdFusion

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