Function expectToBeLeft

expectToBeLeft<E, A>(
value: undefined | Either<E, A>,
): asserts value is Readonly<{ isRight: false; left: E }>
Asserts and narrows the type of the provided Either value to Left.
Type Parameters
- E
- A
Parameters
- value: undefined | Either<E, A>
  The Either value to check
Returns asserts value is Readonly<{ isRight: false; left: E }>
Throws
If the value is undefined or not a Left
- Defined in testing-core/src/lib/expectToBeLeft.ts:12