How to change the Key name of a object

Question

Example I have a object
{
name:"John"
title:"book"
Color :"black"
}

I want to loop through the object and change the name of the title key to start if it equal

and return a new object like this
{
name:"John",
start :"book",
Color:"black"
}

Josh Greig
Here is my code
https://code.sololearn.com/cZXZ3VfCgc95/?ref=app

Answer 1

Sir George wrote, "Josh Greig can you do this on the play Ground Because your approach same quite useful"

Response:

This worked when I fixed your Sololearn code.

const obj = {
name: 'Luke Skywalker',
title: 'Jedi Knight',
age: 23

};

// Assigning to `value` does **not** change the property // value! You need to do `obj[key] = newValue`
function renameKey(obj, fromKey, toKey) {
result = Object.assign({}, obj); // clone so we don't modify the original.
delete result[fromKey];
result[toKey] = obj[fromKey];
return result;
}

console.log(renameKey(obj,'title','start'))

The fixes I made to your code were:
- made k capital for parameters in: function renameKey(obj, fromKey, toKey) {
- added quotes around title and start in this line: console.log(renameKey(obj,'title','start'))

Answer 2

Does this do what you want? Instead of looping through all the key-value pairs, you could use Object.assign to create a clone. Then, you just remove the old key and set the new one.

function renameKey(obj, fromKey, toKey) {
result = Object.assign({}, obj); // clone so we don't modify the original obj.
delete result[fromKey];
result[toKey] = obj[fromKey];
return result;
}

renameKey({
name:"John",
title:"book",
Color :"black"
}, 'title', 'start')

will return {
name:"John",
start :"book",
Color:"black"
}

Answer 3

Josh Greig Here is the full code for replacing keys based on object that maps the values to replace:

https://code.sololearn.com/cYBi89GsnmbO/?ref=app

This will output an array with three objects where keys are replaced. If you want to create a new object out of them, just:

const newTab = replacedItems.reduce((a, b) => Object.assign({}, a, b));

This outputs: {"a_b_c": 1, "d_e_f": 40, "xyz": 50}

Answer 4

Josh Greig can you do this on the play Ground Because your approach same quite useful

Answer 5

Josh Greig oops it generate error when I pass it my argument

Answer 6

Josh Greig 🙏🙏🙏👍👍💯💯 thank you for help the it work Sir

Answer 7

Another alternative solution
https://code.sololearn.com/cA15a1a19847