function sum sum(list: number[]): number Sums the elements in the given list. If you pass a list of numbers, it sums them directly. If you pass a list of objects, provide the key to sum. Examples Example 1 sum([1, 2, 3]); // 6 sum([{ x: 1 }, { x: 2 }], "x"); // 3 Parameters list: number[] Return Type number sum<T extends Record<PropertyKey, number>>(list: T[],key: keyof T,): number Type Parameters T extends Record<PropertyKey, number> Parameters list: T[] key: keyof T Return Type number