matchWithString

matchWithString() performs exhaustive pattern matching on the value of a Clean string primitive. Every possible value must have a processing branch.

A Clean primitive is a wrapped object, so it cannot be used directly as a matcher key. The keys are therefore raw string values. When a key matches, its callback receives the original Clean primitive narrowed to that value, preserving its Primitive, ConstrainedType, or NewType information.

Interactive example

Syntax

Classic signature

function matchWithString<Input extends Primitive<string>, Matcher>(
  input: Input,
  matcher: Matcher
): ReturnType<Matcher[keyof Matcher]>

Curried signature

function matchWithString<Input extends Primitive<string>, Matcher>(
  matcher: Matcher
): (input: Input) => ReturnType<Matcher[keyof Matcher]>

Parameters

• input: a Clean primitive containing a string, including constrained values and new types.
• matcher: an exhaustive object indexed by the possible raw string values. A broad Primitive<string> requires an indexed Record<string, handler>.

Every key must have exactly one handler. TypeScript rejects a missing key or a key outside the input union. The selected handler receives the original Clean object narrowed with Primitive<MatchingValue>.

Return value

The selected handler result, typed as the union of every handler return type.

See also

• matchWithNumber - Numeric primitive equivalent.
• equal - Compares wrapped primitive values.