TypeScript difference between original object and spreaded object

Question

there is a riddle about Typescript I cannot understand:

const  randomFn = (arg: Record<string, unknown>): string => 'kappa'

export type Values = {
    key: string;
};
const values: Values = {
    key: 'kappa'
}

const { ...spread } = values;

randomFn(values)
randomFn(spread) // produce Index signature for type 'string' is missing in type '{ transaction: string; }'.(2345)

Why is Typescript producing errors for spread object when in my understanding it typing should be the same. If we inspect the object in playgroud it is exactly the same for TS compiler. Both original and spreaded.

TS version 4.5.4. Reproduction in Type Script Playground

EDIT: also doing double spread to make it work again .

randomFn({...spread}) // NO error

Answer 1

Spreading loses the type because it has no guarantee that the type of the spread object is the same. Consider this:

const { excluded, ...rest } = object;

Clearly rest can't be the same type as object; there is a key missing!

You can also think of it like this:

const [excluded, ...rest] = array;

That's why spread is not type Values.