Массив уменьшения функции возвращается NAN

Question

У меня есть код, похожий на следующее:

var temp=[{"name":"Agency","y":32,"drilldown":{"name":"Agency","categories":["APPS & SI","ERS"],"data":[24,8]}},{"name":"ER","y":60,"drilldown":{"name":"ER","categories":["APPS & SI","ERS"],"data":[7,53]}},{"name":"Direct","y":60,"drilldown":{"name":"Direct","categories":["APPS & SI","ERS"],"data":[31,29]}}]; 

var reduced=temp.reduce(function (a,b) { 
     return a.y + b.y; 
    }); 
console.log(reduced) // returns NAN 

Answer 1

Вы можете использовать начальное значение и надстройку только одно значение из массива.

var temp=[{"name":"Agency","y":32,"drilldown":{"name":"Agency","categories":["APPS & SI","ERS"],"data":[24,8]}},{"name":"ER","y":60,"drilldown":{"name":"ER","categories":["APPS & SI","ERS"],"data":[7,53]}},{"name":"Direct","y":60,"drilldown":{"name":"Direct","categories":["APPS & SI","ERS"],"data":[31,29]}}]; 
 

 
var reduced = temp.reduce(function (r, a) { 
 
     return r + a.y; 
 
     // ^^^ use the last result without property 
 
    }, 0); 
 
// ^^^ add a start value 
 
console.log(reduced) // r

Answer 2

короткое решение: карта сбора для сбора целых чисел, а также уменьшить его

var temp=[{"name":"Agency","y":32,"drilldown":{"name":"Agency","categories":["APPS & SI","ERS"],"data":[24,8]}},{"name":"ER","y":60,"drilldown":{"name":"ER","categories":["APPS & SI","ERS"],"data":[7,53]}},{"name":"Direct","y":60,"drilldown":{"name":"Direct","categories":["APPS & SI","ERS"],"data":[31,29]}}]; 

var reduced = temp 
       .map(function(obj) { return obj.y; }) 
       .reduce(function(a, b) { return a + b; }); 

console.log(reduced);