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This Lua module is used on approximately 393,000 pages. To avoid major disruption and server load, any changes should be tested in the module's /sandbox or /testcases subpages, or in your own module sandbox. The tested changes can be added to this page in a single edit. Consider discussing changes on the talk page before implementing them.

A helper module to find the most specific chronology portal which actually exists for a given year or decade. Used to simplify linking to a chronology portal.

October 2019 update

All by-year and by-century portals have been deleted. There are now only 8 decade portals, listed in Category:Decades portals.

So all checking for century and year portals has been disabled.

If any of the decade portals are deleted, then this module should be edited to remove that decade from the table existingDecadePortals

Takes one parameter, which must be either a year (e.g. "1879", "1123") or a decade (e.g. "1940s", "730s").

If the parameter is missing, empty, or does not fit the required format, an empty string is returned.

If a portal is found, returns its name without the namespace prefix, e.g.

• for "Portal:1980s" return 1980s
• for "Portal:19th century" return 19th century

If no portal is found, it returns an empty string.

Year parameter

{{#invoke: FindYDCportal | findydcportal |YYYY}} ... where YYYY is a 3- or 4-digit year

Decade parameter

{{#invoke: FindYDCportal | findydcportal |YYY0s}} ... where YYY0s is a 3- or 4-digit decade

Years

• {{#invoke: FindYDCportal | findydcportal |2018}} → 2010s
• {{#invoke: FindYDCportal | findydcportal |1935}} →
• {{#invoke: FindYDCportal | findydcportal |1857}} →
• {{#invoke: FindYDCportal | findydcportal |736}} →
• {{#invoke: FindYDCportal | findydcportal |1800}} →

Decades

• {{#invoke: FindYDCportal | findydcportal |2000s}} → 2000s
• {{#invoke: FindYDCportal | findydcportal |1940s}} →
• {{#invoke: FindYDCportal | findydcportal |560s}} →

Missing parameter

• {{#invoke: FindYDCportal | findydcportal}} →

Empty parameter

• {{#invoke: FindYDCportal | findydcportal | }} →

Invalid parameter

• {{#invoke: FindYDCportal | findydcportal | 1927-related}} →
• {{#invoke: FindYDCportal | findydcportal | Swedish chef}} →

If the parameter is a year:

1. If the year portal exists, return its name.
   Otherwise try the decade.
2. If the decade portal exists, return its name.
   Otherwise try the century
3. If the century portal exists, return its name.
   Otherwise return an empty string

If the parameter is a decade:

1. If the decade portal exists, return its name.
   Otherwise try the century
2. If the century portal exists, return its name.
   Otherwise return an empty string

• Template:Portal
• Template:Portalbar
• Wikipedia:Portals