javascript二维数组(18)多个数组按照对应为准相加求和生成新的数组2

在数组var a=[
{name:“1”,pre1_day_off:1,pre2_day_off:1,pre3_day_off:1},
{name:“2”,pre1_day_off:2,pre2_day_off:2,pre3_day_off:1},
{name:“3”,pre1_day_off:3,pre2_day_off:3,pre3_day_off:1}
]中，如何将三个对象中的多个如pre1_day_off1相加，pre2_day_off2相加，pre3_day_off3相加，生成新的数组[sum1,sum2,sum2…sumn]

使用类似的逻辑来对数组中的对象进行求和。以下是一个示例代码：

var a = [
    {
   name:"1"