Lodash sumBy method
语法
_.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).
参数
array (Array) − The array to iterate over.
[iteratee=_.identity] (Function) − The iteratee invoked per element.
输出
(number) − Returns the sum.
实例
var _ = require('lodash');
var values = [{ 'n': 1 }, { 'n': 2 }, { 'n': 3 }];
var result = _.sumBy(values, function(item) { return item.n; });
console.log(result);
result = _.sumBy(values, 'n');
console.log(result);
Save the above program in
tester.js. Run the following command to execute this program.
Command
输出
