Function isNullish

isNullish(value: unknown): value is undefined | null
Checks if value is null or undefined.
Parameters
- value: unknown
  The value to check.
Returns value is undefined | null
Returns true if value is null or undefined, else false.
Example
```
isNullish(null)
// => true

isNullish(undefined)
// => true

isNullish('Hello, world!')
// => false
```
- Defined in isNullish.ts:23