how to create dynamic multi-dimensional array of objects with in javascript

Question

I have an array of objects that has information about cars. I want to grouping on categoryId

var car = [
  { category: 1, model: "bmw" },
  { category: 1, model: "benz" },
  { category: 1, model: 'ford' }
  { category: 2, model: "kia" },
  { category: 2, model: "fiat" },
  { category: 3, model: "mg" },
];

I want this result

[  
  [
    { category: 1, model: 'bmw' },
    { category: 1, model: 'benz' },
    { category: 1, model: 'ford' }
  ],
  [ 
    { category: 2, model: 'kia' },
    { category: 2, model: 'fiat' }
  ],
  [ 
    { category: 3, model: 'mg' }
  ]
]

this is my solution but I want a way for this result based on reduce or ... I dont want to use if in forEach

let groupedCars = [];
cars.forEach((car) => {
  if (!groupedCars[car.category]) {
    groupedCars[car.category] = [];
  }
  groupedCars[car.category].push(car);
});

"I want a way for this result based on reduce" - why? What do you think is wrong with the current code? — Bergi
– Bergi, Commented Jan 7, 2021 at 15:33

phi-rakib · Accepted Answer · 2021-01-07 15:22:40Z

1

Solution using Array.prototype.reduce() method. Traverse the array and group it by category using reduce and at last, use Object.values() to get the result.

const car = [
  { category: 1, model: 'bmw' },
  { category: 1, model: 'benz' },
  { category: 1, model: 'ford' },
  { category: 2, model: 'kia' },
  { category: 2, model: 'fiat' },
  { category: 3, model: 'mg' },
];

const ret = Object.values(
  car.reduce((prev, c) => {
    const p = prev;
    const key = c.category;
    p[key] = p[key] ?? [];
    p[key].push({ ...c });
    return p;
  }, {})
);
console.log(ret);

answered Jan 7, 2021 at 15:22

phi-rakib

3,3222 gold badges12 silver badges21 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

shyam · Accepted Answer · 2021-01-07 15:01:50Z

0

Not clear what you mean by result based on ES6. But, you could try using reduce method.

NOTE: Javascript arrays start with index 0 so, you might need to add some logic in your code to fix that

answered Jan 7, 2021 at 15:01

shyam

9,3864 gold badges32 silver badges45 bronze badges

1 Comment

Mohammad Yaser Ahmadi Over a year ago

yes I want to use reduce or like this... how can I use of reduce to gain this result?

Collectives™ on Stack Overflow

how to create dynamic multi-dimensional array of objects with in javascript

2 Answers 2

Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related