Группировка объектов

var data1 = [ 
{ month:"Jan", category:"Final", value: "141" }, 
{ month:"Jan", category:"Raw Material", value: "3 513" }, 
{ month:"Jan", category:"Raw material class B", value: "1 551" }, 
{ month:"Jan", category:"Scrap", value: "116" }, 
{ month:"Jan", category:"Trading", value: "59" }, 
{ month:"Jan", category:" ", value: " " }, 
{ month:"Feb", category:"Final", value: "144" }, 
{ month:"Feb", category:"Raw Material", value: "3 631" }, 
{ month:"Feb", category:"Raw material class B", value: "1 591" }, 
{ month:"Feb", category:"Scrap", value: "116" }, 
{ month:"Feb", category:"Trading", value: "30" }, 
{ month:"Feb", category:" ", value: " " }, 
]; 
 
console.log(data1.reduce((result, {category, value}) => { 
  let target = result.find(row => row.category == category); 
  if(!target) { 
    target = {category, values: []}; 
    result.push(target); 
  }; 
  target.values.push(value); 
  return result; 
}, []));