Consolidation behavior

Should the unique operation keep the first value with a given surrogate key or the last, and at what index? Is there reason to make it author-configurable?
```js
const data = [
    { id: 1, name: "1a" },
    { id: 2, name: "2a" },
    { id: 1, name: "1b" },
];
data.uniqueBy(v => v.id)[0].name; // ???
```