Checkboxes based on is blank or not is blank?

1

With the introduction of flexible fieldnames in 5.2.0 we can use the following with actual tiddler titles used as the fieldname.

<$checkbox field="fieldname" checked="true" unchecked="" default=""></$checkbox>

In the above the checkbox will toggle between true and empty.

Question:
I would like the check box to respond as true if it contains true or any other values, just not empty.
Can anyone see how to do this with minimal changes?

2

Maybe

<$checkbox field="fieldname" checked={{{[{!!fieldname}trim[]!is[blank]then{!!fieldname}else[true]]}}} unchecked="" 
default=""   >My test</$checkbox>
3

Dang it, you beat me to the punch. I didn’t think of trimming.

<$checkbox field="fieldname" checked={{{ [{!!fieldname}!is[blank]] [[true]] +[first[]] }}} unchecked="" default=""></$checkbox>
4

Thanks I will test these soon, they both look good,

Marks comparison with the actual field value and Charlies choose the “first[]” are great ideas.

Thanks heaps, tony