isLeft

isLeft<L>(x): x is Left<L>

Check whether given x is of type Left.

Example

isLeft({left: 123})
// => true

isLeft({right: 456})
// => false

isLeft({left: 1234} as Either<number, string>)
// => x is Left<number>

Type Parameters

• L

The Left type.

Parameters

x

unknown

The value to check.

Returns

x is Left<L>

true if x is a Left, false otherwise.