[voraa]

Без полифилов и покороче

let allData = [
  { idStandard: 1278, valueDecNew: 8 },
  { idStandard: 1279, valueDecNew: 3 },
  { idStandard: 1280, valueDecNew: 6 },
  { idStandard: 1284, valueDecNew: 56 }
 ]
 
let params = [
  { idStandard: 1278, valueDecNew: 0 },
  { idStandard: 1279, valueDecNew: 0 },
  { idStandard: 1282, valueDecNew: 0 }
]

let result = params.concat(allData.filter (function (x) {
    return ! params.some (function (y) {return x.idStandard === y.idStandard})
}))

console.log(result)