Template:If empty

Template:If empty is imported from Template:If empty on Wikipedia.

This template is imported from the English Wikipedia. Although the visual appearance might be different, the functionality is identical. Please refer to the Wikipedia page for detailed documentation.

Template:If empty invokes function main in Module:If empty using Lua.

This template is used inside other templates. It 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. The template provides a fallback order, similar to a try catch based "It is easier to ask for forgiveness than permission" (EAFP) 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".