I didn't find the answer here, so please to do no write that it is duplicate!
My problem is as follows. I have such an array with objects:

```
Items: [

        {  groups: [{…}]
          id: 1
          name: "Test Name"
          _test: null
          _test2: 0.02867696
        },
        {  groups: [{…}]
          id: 2
          name: "Test Name2"
          _test: null
          _test2: 0.02867696
        },
  ]

```

I need to change each object fields names, such as id, name to topicId and topicName. The rest on the data I need to keep as it is and return back array with changed objects.  

I wrote such a function to get access to every object:

```
function changeFields(data) {
  for (const key of Object.keys(data)) {
    data[key].map(item => {

    })
  }
}

```

but I do not know what to do next.