Update the keys in an object array dynamically

Question

How would I go about updating the keys in an object array dynamically ?

I have the following string array called headers:

headers = ['col1', 'col2', 'col3', 'col4']

I have the object array called rows:

const rows = [
{
  column1: 'value1',
  column2: 'value2',
  column3: 'value3',
  column4: 'value4'
}, 
{
  column1: 'value5',
  column2: 'value6',
  column3: 'value7',
  column4: 'value8'
}
];

I would like to update the keys inside rows so that it matched with the values of the headers done dynamically without hardcoding it.

Expected output to be a string array:

{
  col1: 'value1',
  col2: 'value2',
  col3: 'value3',
  col4: 'value4'
}, 
{
  col1: 'value5',
  col2: 'value6',
  col3: 'value7',
  col4: 'value8'
}

If you have code that doesn't quite work, you should add that to your post. — jarmod, Oct 15 '21 at 14:33
Does this answer your question? [JavaScript: Object Rename Key](https://stackoverflow.com/questions/4647817/javascript-object-rename-key) — jarmod, Oct 15 '21 at 14:35
How would any "dynamic" code know, that `column1` was renamed to `col1` and not `col4` ? — derpirscher, Oct 15 '21 at 14:36

scr2em · Accepted Answer · 2021-10-15T21:03:42.460

0

if you have trouble understanding any part let me know

function convertKeys(array , newKeys){
 return array.map(row=>{
    return Object.fromEntries(Object.entries(row).map((x,i)=> {
      x[0] =headers[i]
      return x
    }))
  })
}

convertKeys(rows,headers)

or instead of relying on the order you can use something like this

let newKeys = [
  ["column1", "col1"],
  ["column2", "col2"],
  ["column3", "col3"],
  ["column4", "col4"],
]
function convertKeys(array , newKeys){

  array.forEach(obj=>{
   for (let i = 0 ; i < newKeys.length ; i++){
     let [oldKey,newKey] = newKeys[i]
     if(obj.hasOwnProperty(oldKey)){
       obj[newKey] = obj[oldKey]
       delete obj[oldKey]
     }
       }
 })
  return array
}

convertKeys(rows,newKeys)

edited Oct 15 '21 at 21:03

answered Oct 15 '21 at 14:36

scr2em

974
8
17

Seems to require the properties of each object to have been inserted into the object in the correct order. Ideally, would use a mapping of old name to new name for flexibility. – jarmod Oct 15 '21 at 14:40
That heavily relies on the correct order of `Object.entries`, which is (more or less) the order in which the properties have been created in the object. – derpirscher Oct 15 '21 at 14:41
Your check with `if (obj[oldKey])` is not sufficient. Consider the object `{column1: 0, column2: "", column3: false}` Here none of they keys will be replaced ... – derpirscher Oct 15 '21 at 20:56
changed it to hasOwnProperty – scr2em Oct 15 '21 at 21:03

Update the keys in an object array dynamically

1 Answers1