var a = new Array(30), b = {}, data = []

a.fill(new Date('2019-11-12 00:00:00'))

a.forEach(function (v, i) {

  var t = new Date(v.valueOf() - i * 86400000),

      k = t.toLocaleDateString(), d = k.split(/(?:\/|-)/)

  d.shift()

  b[d.join('_')] = { month: d[0], dayOfMonth: d[1] }

})

// 假设row为数据库统计结果

var rows = [{ _id: { month: 11, dayOfMonth: 9 }, totalOrders: 1, totalAmount: 10 }]

for(var k in b){

  var val = b[k]

  rows.forEach(function (v, i) {

    var key = v._id.month + '_' + v._id.dayOfMonth

    data.push(key == k ? v : { _id: val, totalOrders: 0, totalAmount: 0 })

  })

}

console.log(data)