TypeScript how to format array of object to array of json

Question

I have posted data like _attachments variable:

I want to prepare that data to insert as the following structure:

"_attachments": [
  {
    "container": "string",
    "fileName": "string",
    "name": "string",
    "mime": "string",
    "size": 0
  }
]

But what i have done:

for(let key in _attachments) {
  job._attachments[key]['container']  = _attachments[key]['container'];
  job._attachments[key]['fileName']  = _attachments[key]['fileName'];
  job._attachments[key]['name']      = _attachments[key]['name'];
  job._attachments[key]['mime']      = _attachments[key]['mime'];
  job._attachments[key]['size']      = _attachments[key]['size'];
}

give this error:

 Unprocessable Entity

Note: I'm using loopback.

Answer 1

Just add this to your attachment.josn:

"id": {
  "type": "string",
  "id": true,
  "defaultFn": "uuid"
}

and no need to loop the data.

Answer 2

From the screen shot _attachments seems to be an array; if that is that case you should not use for...in to iterate over it but for..of. for..in will return all enumerable properties including potentially "unwanted" ones

See the bottom of this excellent MDN resource for details (for..of is available in Typescript)

for (let index of _attachments) {
...
}

Even better, use a map

const result  = _attachments.map( att => ...)

Also the structure you map to seem identical to the original structure, why not use a direct assignment ?