Javascript: Initialize some property for each object in a list

[kirantambe]

I want to do this
this.someList.forEach(item => item.someProperty = 'Some Value');

But i get these
no-return-assign Arrow function should not return assignment
no-param-reassign Assignment to property of function parameter 'item'

How do i do it diffrently?

[ljharb]

First,

this.someList.forEach(item => { item.someProperty = 'Some Value'; });

since you're not trying to return a value from the arrow function.

As for no-param-reassign, the intent is specifically not to mutate - if item is a plain object, you could do:

const newList = this.someList.map(item => ({ ...item, someProperty: 'Some Value' }));

[kirantambe]

Yes they are plain objects so ill use map.
Didnt know about the ... syntax.
Thanks