How do I override a property in typescript?

This may not be possible due to current language limitations, but I'm using the latest TS (1.8.10) and am running into an issue with the ui-grid typings. The isRowSelectable property on IGridOptions is defined as an optional boolean but the documentation says it's a function (and it is). I am trying to override the boolean property to be a function that returns a boolean.

Normally, I just extend the typing interface and do what I need, but that's not working in this case. Here's what I have:

interface ISelectionGridOptions extends IGridOptions {
  isRowSelectable: (row: IGridRowOf<Profile>) => boolean;
}

Where the relevant field in IGridOptions is:

export interface IGridOptions {
  ...
  isRowSelectable?: boolean
  ...
}

And the error I'm getting is:

(41,11): error TS2430: Interface 'ISelectionGridOptions' incorrectly extends interface 'IGridOptionsOf<any>'.
  Types of property 'isRowSelectable' are incompatible.
    Type '(row: IGridRowOf<Profile>) => boolean' is not assignable to type 'boolean'.

Short of fixing the core typings definitions, is there a way to fix this in my code?

Answer

November 3, 2021

KyleMit

Update for TS 3.5+

You can add this utility type to your project:

type Modify<T, R> = Omit<T, keyof R> & R;

And then use it like this:

type ISelectionGridOptions = Modify<IGridOptions, {
  isRowSelectable: (row: IGridRowOf<Profile>) => boolean;
}>

Demo in TS Playground

Answer

Update for TS 3.5+

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