replaceFieldTypes

Note

This is a point-in-time snapshot of the API documentation from January 2026. Going forward, we will not be maintaining a public copy of these references, and recommend users to refer to the built-in signature helpers available in the Hack LSP instead for complete and up-to-date information.

Adjusts the field types (width and subtype) of a pattern to match what is in a skeleton

public function replaceFieldTypes(
  string $pattern,
  string $skeleton,
): string;

Example: given an input pattern of "d-M H:m", and a skeleton of "MMMMddhhmm", the output pattern will be "dd-MMMM hh:mm".

Parameters

• string $pattern - Input pattern
• string $skeleton - The skeleton is a pattern containing only the variable fields. For example, "MMMdd" and "mmhh" are skeletons.

Returns

• string - - Pattern adjusted to match the skeleton fields widths and subtypes.