Template:Link if exists/doc

This is a documentation subpage for Template:Link if exists.
It may contain usage information, categories and other content that is not part of the original template page.

This template is used on approximately 292,000 pages.
To avoid major disruption and server load, any changes should be tested in the template's /sandbox or /testcases subpages, or in your own user subpage. The tested changes can be added to this page in a single edit. Consider discussing changes on the talk page before implementing them.

Due to a server limit of 500 "expensive parser function" calls (e.g. #ifexist:, PAGESIZE:, and PAGESINCATEGORY:), this template will only work properly if the page using it has not already exceeded the limit. When the limit is exceeded, the page using this template or module is categorised in Category:Pages with too many expensive parser function calls. (further information)

This template uses Lua:

Module:Link if exists (sandbox)

Usage

Positional parameters

1: Title of page to link to. Wikilinked if an article exists, otherwise unlinked.
2: (optional) Text to display, defaults to positional parameter 1

Named parameters

nsp: The namespace to try to link to (e.g., |nsp=Category). This namespace is not displayed.
prefix: A string to prefix the link. This prefix is displayed if a link is found.
color: Color of text if no link is found
hide_display: If page does not exist and if hide_display is non-empty, do not display anything

Examples

A page which exists:
{{Link if exists|Japan}} → Japan
A page which does not exist:
{{Link if exists|The exciting story of paint drying in a small town in Japan one day in April 1927}} → The exciting story of paint drying in a small town in Japan one day in April 1927
Another page which exists, prefix specified:
{{Link if exists|History|prefix=Portal}} → Portal:History
A page which does not exist, nsp specified:
{{Link if exists|Computing in 1066|nsp=Portal}} → Computing in 1066
Use of second positional parameter, page exists:
{{Link if exists|target|word}} → word
Use of second positional parameter, page does not exist:
{{Link if exists|agrp|,asmd}} → ,asmd
Page does not exist, color parameter:
{{Link if exists|agrp|color=#888}} → agrp
Page does not exist, hide_display parameter:
{{Link if exists|agrp|hide_display=1}} →

TemplateData

This is the TemplateData for this template used by TemplateWizard, VisualEditor and other tools. See a monthly parameter usage report for Template:Link if exists in articles based on its TemplateData.

TemplateData for Link if exists

Link to a page if it exists, otherwise leave unwikilinked

Template parameters
This template prefers inline formatting of parameters.
Parameter		Description	Type	Status
Title	`1`	Title of page to link to	Page name	required
Display	`2`	Text to display Default Value of title parameter	String	optional
Namespace	`nsp`	The namespace of the title to link to Suggested values `Template` `Category` `Wikipedia`	String	optional
Prefix	`prefix`	String to add a prefix to the title Suggested values `Template` `Category` `Wikipedia`	String	optional
Color	`color`	HTML color of text if no link is displayed	String	optional
Hide display	`hide_display`	If non-empty, hide display string if not existing	Boolean	optional