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.

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.

number

The sum of all the numbers as determined by the getValue function.

sumBy([{ a: 1 }, { a: 2 }, { a: 3 }], (x, i) => x.a * i); // Returns: 8
sumBy([], () => 1); // Returns: 0