What causes my array of objects to be assigned numbers when copying a JSON data file using Object.assign?

Question

What causes my array of objects to be assigned numbers when copying a JSON data file using Object.assign?

I have a JSON file that I need to transfer to my local object using new Object and Object Assign:

let newObj = new Object(); 
Object.assign(newObj, MyData.map(data => ({
personal_id : data._id,
idx : data.index,
voiceLines : data.tags
})));

console.log(newObj);

After checking the returned result, it appears as though the JSON data was successfully copied into a simple array of objects. However, the output includes extra numerical keys at the beginning like '1': {...}. How can I remove these numbers?

javascript arrays object

Answer 1

Answer №1

It's interesting that both new Object() and Object.assign are used in this example:

const MyData =
[
{
_id: '62bab08c10365bb88f81cdf5',
index: 1,
tags: [
  'non laborum cillum commodo velit culpa commodo',
  'nisi aute magna laborum ut cillum velit',
  'in veniam ullamco officia aute deserunt ex',
  'dolor ullamco aliqua laborum ullamco officia mollit',
  'fugiat aliquip nostrud deserunt fugiat veniam veniam',
  'culpa eu irure ullamco ea deserunt ullamco',
  'labore quis quis enim magna duis cupidatat'
]
},
{
_id: 'abcdefghijklmnopqrstuvwx',
index: 2,
tags: [
  'The grand old duke of York',
  'he had ten thousand men',
  'he ran them up that hill',
  'and made a deal with god',
  'to swap our places',
]
}
];


let newObjects = MyData.map(data => 
{
  let newObj = new Object();
  Object.assign(newObj, 
    {
      persId : data._id,
      idx : data.index,
      voiceLines : data.tags
    });
   return newObj;
}
);

console.log(newObjects);

Answer 2

It's interesting that both new Object() and Object.assign are used in this example:

const MyData =
[
{
_id: '62bab08c10365bb88f81cdf5',
index: 1,
tags: [
  'non laborum cillum commodo velit culpa commodo',
  'nisi aute magna laborum ut cillum velit',
  'in veniam ullamco officia aute deserunt ex',
  'dolor ullamco aliqua laborum ullamco officia mollit',
  'fugiat aliquip nostrud deserunt fugiat veniam veniam',
  'culpa eu irure ullamco ea deserunt ullamco',
  'labore quis quis enim magna duis cupidatat'
]
},
{
_id: 'abcdefghijklmnopqrstuvwx',
index: 2,
tags: [
  'The grand old duke of York',
  'he had ten thousand men',
  'he ran them up that hill',
  'and made a deal with god',
  'to swap our places',
]
}
];


let newObjects = MyData.map(data => 
{
  let newObj = new Object();
  Object.assign(newObj, 
    {
      persId : data._id,
      idx : data.index,
      voiceLines : data.tags
    });
   return newObj;
}
);

console.log(newObjects);

What causes my array of objects to be assigned numbers when copying a JSON data file using Object.assign?

Answer №1

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