isPropertyNotNull<T, P>(property): ((obj) => obj is { [X in string | number | symbol]: X extends P ? NonNull<T[X]> : T[X] })
Returns a type guard function, which receives an object and checks if the given property is not null.
Narrows the type of the given property within the object type from T | null to just T.
Example:
incoming type is { a: number, b: string | null }
outgoing type of returned type guard from propertyNotNull('b') is { a: number, b: string }
Type Parameters
T
P extends string | number | symbol
Parameters
property: P
name of the property to check
Returns ((obj) => obj is { [X in string | number | symbol]: X extends P ? NonNull<T[X]> : T[X] })
(obj): obj is { [X in string | number | symbol]: X extends P ? NonNull<T[X]> : T[X] }
Parameters
obj: T
Returns obj is { [X in string | number | symbol]: X extends P ? NonNull<T[X]> : T[X] }
Returns a type guard function, which receives an object and checks if the given property is not null. Narrows the type of the given property within the object type from T | null to just T.
Example:
incoming type is { a: number, b: string | null }
outgoing type of returned type guard from propertyNotNull('b') is { a: number, b: string }