Template:First-of
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[edit] Template documentation
This template takes up to four parameters, returning the first one that has any content. In contrast to default values of template parameters, this method is not sensitive to the difference between undefined (Null) and empty string.
Background
Normally, a template parameter evaluated with a default value, such as "{{{parameter1 | MISSING }}}" will return the default value ("Missing") if not appearing in the template call, but an empty string ("") if the template call contains:
| ... | parameter1= | ...
Usage
{{First-of| {{{primary|}}} | {{{alternative|}}} | DefaultValue }}
{{First-of| A | B | C }}
Result in:
DefaultValue A
