isNotNil ​
Checks if the given value is not null nor undefined.
This function can also serve as a type predicate in TypeScript, narrowing the type of the argument to ensure it is not nullable.
Signature ​
typescript
function isNotNil<T>(x: T | null | undefined): x is T;Parameters ​
x(T | null | undefined): The value to test if it is not null nor undefined.
Returns ​
(x is T): True if the value is not null nor undefined, false otherwise.
Examples ​
typescript
// Here the type of `arr` is (number | undefined)[]
const arr = [1, undefined, 3];
// Here the type of `result` is number[]
const result = arr.filter(isNotNil);
// result will be [1, 3]