Given an array of objects, how do I replace the key name with another whilst keeping the value from the original key?

Question

I'm trying to take an array of objects and, without mutating the original array, rename a specific key in each object.

I've created a new variable and assigned it to the result of using 'map' on my original array (to avoid mutation). Within the 'map' method, I've tried to deconstruct the 'keyToChange' parameter and spread the rest of the values to the 'newKey'.

const renameKeys = (array, keyToChange, newKey) => {
  const spreadArray = array.map(({keyToChange: newKey, ...rest}) => ({newKey, ...rest}));
    return spreadArray;
   };

The above code returns 'newKey: [undefined]' followed by the original array of objects.

Any help would be greatly appreciated.

Nina Scholz · Accepted Answer · 2019-06-01 15:04:10Z

4

You need a computed property name instead of a (not given) propery keyToChange.

const spreadArray = array.map(({ [keyToChange]: newKey, ...rest }) => ({ newKey, ...rest }));
//                               ^^^^^^^^^^^^^

answered Jun 1, 2019 at 15:04

Nina Scholz

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user-9725874 · Accepted Answer · 2019-06-01 15:09:39Z

3

Use square brackets notation if you want to use dynamic value as key. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Property_accessors */

 const spreadArray = array.map(({ [keyToChange]: newKey, ...rest}) => ({newKey, ...rest}));

answered Jun 1, 2019 at 15:09

user-9725874

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Maheer Ali · Accepted Answer · 2019-06-01 15:04:07Z

2

If you want a an expression to be the key to be changed then use square brackets around it []

const renameKeys = (array, keyToChange, newKey) => {
  const spreadArray = array.map(({[keyToChange]: newKey, ...rest}) => ({newKey, ...rest}));
    return spreadArray;
};

answered Jun 1, 2019 at 15:04

Maheer Ali

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