sumBy source npm
_.sumBy(array, [iteratee=_.identity])
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).
Arguments
- array (Array)
The array to iterate over.
- [iteratee=_.identity] (Function|Object|string)
The function invoked per element.
Returns (number)
Returns the sum.
Example
var objects = [
{ 'n': 4 },
{ 'n': 6 }
];
_.sumBy(objects, function(o) { return o.n; });
// => 10
// using the `_.property` callback shorthand
_.sumBy(objects, 'n');
// => 10