Function sumMap

sumMap<T>(values: Iterable<T>, callback: (value: T) => number | null): number
Computes the sum of mapped values from an iterable, where null values contribute 0.
Type Parameters
- T
Parameters
- values: Iterable<T>
  iterable of input values
- callback: (value: T) => number | null
  mapping function (value: T) => number | null
Returns number
sum of non-null mapped values (0 if empty or all null)
Example
```
sumMap([1, 2, 3], x => x * x); // 14 (1+4+9)

const objects = [{x: 1}, {x: 2}, {x: 3}];
sumMap(objects, obj => obj.x ?? null); // 6 (1+2+3)
```
- Defined in functions.ts:88