Function when

when<input, predicate>(predicate): GuardP<input, predicate extends ((value) => value is infer narrowed)
? narrowed
: never>
P.when((value) => boolean) returns a pattern which matches if the predicate returns true for the current input.

Read the documentation for P.when on GitHub
Type Parameters
- input
- predicate extends ((value) => unknown)
Parameters
- predicate: predicate
Returns GuardP<input, predicate extends ((value) => value is infer narrowed)
? narrowed
: never>
Example
```
match<{ age: number }>(value)
  .with({ age: P.when(age => age > 21) }, (x) => 'will match if value.age > 21'
  )
```
- Defined in node_modules/ts-pattern/dist/patterns.d.ts:176
when<input, narrowed, excluded>(predicate): GuardExcludeP<input, narrowed, excluded>
Type Parameters
- input
- narrowed
- excluded
Parameters
- predicate: ((input) => input is narrowed)
  - - (input): input is narrowed
    - Parameters
      input: input
      Returns input is narrowed
Returns GuardExcludeP<input, narrowed, excluded>
- Defined in node_modules/ts-pattern/dist/patterns.d.ts:177