Function sumBy

sumBy<T>(xs: readonly T[], fn: (x: T) => number): number
Sum the numeric projection of each element. Empty input returns 0.

Dual API — works data-first or curried for use in pipe.
Type Parameters
- T
Parameters
- xs: readonly T[]
- fn: (x: T) => number
Returns number
Example
```
pipe(
    orders,
    Arrays.sumBy((o) => o.total),
  )
```
- Defined in arrays/aggregate.ts:15
sumBy<T>(fn: (x: T) => number): (xs: readonly T[]) => number
Sum the numeric projection of each element. Empty input returns 0.

Dual API — works data-first or curried for use in pipe.
Type Parameters
- T
Parameters
- fn: (x: T) => number
Returns (xs: readonly T[]) => number
Example
```
pipe(
    orders,
    Arrays.sumBy((o) => o.total),
  )
```
- Defined in arrays/aggregate.ts:16