• This method is like _.sum except that it accepts iteratee which is invoked for each element in array to generate the value to be summed. The iteratee is invoked with one argument: (value).

    Type Parameters

    • T

    Parameters

    • collection: undefined | null | List<T>
    • Optionaliteratee: string | ((value: T) => number)

      The iteratee invoked per element.

    Returns number

    Returns the sum.

    var objects = [{ 'n': 4 }, { 'n': 2 }, { 'n': 8 }, { 'n': 6 }];

    _.sumBy(objects, function(o) { return o.n; });
    // => 20

    // using the `_.property` iteratee shorthand
    _.sumBy(objects, 'n');
    // => 20