Template:If empty/doc

This is a template documentation subpage for Template:If empty.
It contains usage information, categories, interlanguage links and other content that is not part of the original template page.

This template takes any number of parameters and returns the first found to be defined and non-empty. If none is found, nothing is returned. By writing {{if empty|a|b|c}} instead of {{#if:a|a|{{#if:b|b|c}}}}, expression a and b do not have to be repeated and evaluated twice.

This is designed to be used inside other templates. It provides a fallback order, similar to a try/catch based programming style.

Typical usage is like this:

{{If empty |{{{logo|}}} |{{{image|}}} |{{{picture|}}} |default.svg}}

— Return {{{logo|}}} if it has a value; else {{{image|}}} if it has a value; else {{{picture|}}} if it has a value; else return "default.svg".

This returns the first of the parameters logo, image and picture that is defined and non-empty, otherwise "default.svg".

See Wikipedia:Template:If empty for complete documentation.