1.6.1 • Published 4 years ago
@ulangi/assert v1.6.1
assert
This library is used with TypeScript support in production code where you want to reduce/infer type of certain variables.
Here is one good example:
type User = { userId: string }
// Assume that we have getUser() that returns either null or an User object
funtion getUser(): null | User {
}
// When we know that getUser() will certainly not return null beyond this point,
// use assertExists to reduce the type to User.
const { userId } = assertExists(getUser())API:
| Method | Explanation |
|---|---|
assertExists | Assert that variable should not be neither null nor undefined. |
assertType | Assert the type of variable using a typeguard function. |
assertRequired | Assert variable to follow a certain Joi schema whose properties are required unless stated otherwise. |
assertOptional | Assert variable to follow a certain Joi schema whose properties are optional unless stated otherwise. |