Function mustMatch

mustMatch<P extends Pattern>(
    specimen: any,
    patt: P,
    label?: string | number,
): asserts specimen is TypeFromPattern<P>
Type-narrowing mustMatch: narrows specimen after the call. Throws if the specimen does not match.
Type Parameters
- P extends Pattern
Parameters
- specimen: any
  The value to test.
- patt: P
  The pattern to match against.
- Optionallabel: string | number
  Optional label for error messages.
Returns asserts specimen is TypeFromPattern<P>
Example
```
mustMatch(value, M.string());
value; // narrowed to string
```
- Defined in patterns/src/type-from-pattern.ts:425