The method assign JS

Question

There is a function that changes the key "certificate" to "certificate_car". Is there a way to improve the function by using directly the assign method to change the array? Is it possible?

const arr = [{
    "name": "BMW",
    "price": "55 000",
    "country": "Germany",
    "certificate": "yes"
  },
  {
    "name": "Mercedes-benz",
    "price": "63 000",
    "country": "Germany",
    "certificate": "yes"
  },
  {
    "name": "Mitsubishi",
    "price": "93 000",
    "constructor": "Bar John",
    "door": "3",
    "country": "Japan",
  },
  {
    "name": "TOYOTA",
    "price": "48 000",
    "max_people": "7",
    "country": "Japan",
    "certificate": "yes"
  },
  {
    "name": "Volkswagen",
    "price": "36 000",
    "constructor": "Pier Sun",
    "country": "Germany",
    "certificate": "no"
  },
];

function certificateCar(arr) {
  return arr.map(function(item) {
    let itemCar = {};
    let newItem = Object.assign({}, item);
    Object.keys(newItem).forEach(item => {
      itemCar[item.replace("certificate", "certificate_car")] = newItem[item]
    });
    return itemCar;
  })
}
console.log(certificateCar(arr))

score 3 · Accepted Answer · answered Apr 13 '19 at 15:55

You can use destructuring and change the desired key name and keep the rest as it is

const arr = [{"name":"BMW","price":"55 000","country":"Germany","certificate":"yes"},{"name":"Mercedes-benz","price":"63 000","country":"Germany","certificate":"yes"},{"name":"Mitsubishi","price":"93 000","constructor":"Bar John","door":"3","country":"Japan",},{"name":"TOYOTA","price":"48 000", "max_people":"7","country":"Japan","certificate":"yes"},{"name":"Volkswagen","price":"36 000", "constructor":"Pier Sun","country":"Germany","certificate":"no"}, ];

const certificateCar = (arr) =>
   arr.map(({certificate,...rest}) =>({...rest,certificate_car:certificate}))

console.log(certificateCar(arr))

Your version makes the code much easier, but the question was about the assign method — Gregori Roberts, Apr 13 '19 at 16:11
@LoveGIAS you can use `Object.assign({},{...rest,certificate_car:certificate})` inside map — Code Maniac, Apr 13 '19 at 16:13

Emin Qasimov · Answer 2 · 2019-04-13T16:28:20.797

 

    const arr = [{
        "name": "BMW",
        "price": "55 000",
        "country": "Germany",
        "certificate": "yes"
      },
      {
        "name": "Mercedes-benz",
        "price": "63 000",
        "country": "Germany",
        "certificate": "yes"
      },
      {
        "name": "Mitsubishi",
        "price": "93 000",
        "constructor": "Bar John",
        "door": "3",
        "country": "Japan",
      },
      {
        "name": "TOYOTA",
        "price": "48 000",
        "max_people": "7",
        "country": "Japan",
        "certificate": "yes"
      },
      {
        "name": "Volkswagen",
        "price": "36 000",
        "constructor": "Pier Sun",
        "country": "Germany",
        "certificate": "no"
      },
    ];

    function certificateCar(arr) {

      return arr.map(function(item) {
        let newItem = {}
        delete Object.assign(newItem, item, {["certificate_car"]: item["certificate"] })["certificate"];
        return newItem
      })
      
    }
    console.log(certificateCar(arr))

if you want to do this with assign method this will be better than replacing keynames

yes, you are right, but the question was about the assign method — Gregori Roberts, Apr 13 '19 at 16:13
I changed it, this link will help you https://stackoverflow.com/questions/4647817/javascript-object-rename-key — Emin Qasimov, Apr 13 '19 at 16:30

The method assign JS

2 Answers2