sumBy
Import from @varavel/vdl-plugin-sdk/utils/math.
function sumBy<T>(items, getValue): number;
Calculates the sum of an array of numbers when applying
the getValue function to each element.
If the array is empty, this function returns 0.
Type Parameters
| Type Parameter | Description |
|---|---|
T | The type of elements in the array. |
Parameters
| Parameter | Type | Description |
|---|---|---|
items | readonly T[] | An array to calculate the sum. |
getValue | (element, index) => number | A function that selects a numeric value from each element. It receives the element and its zero‑based index in the array. |
Returns
number
The sum of all the numbers as determined by the getValue function.
Example
sumBy([{ a: 1 }, { a: 2 }, { a: 3 }], (x, i) => x.a * i); // Returns: 8
sumBy([], () => 1); // Returns: 0