core.isdefined | Medplum
isDefined() function
Helper function to narrow a type by excluding undefined/null values.
Signature:
export declare function isDefined<T>(value: T | undefined | null): value is T;
Parameters
| Parameter | Type | Description |
|---|---|---|
| value | T | undefined | null | The value to refine |
Returns:
value is T
boolean
Example
const arr: Array<number | undefined> = [1,undefined];
const refined: Array<number> = arr.filter(isDefined);