cannot be used as an index type.ts(2538) Any idea how to get rid of this type error?

[Leftium]

...cannot be used as an index type.ts(2538)

type Field is defined by datatables and is used to iterate the rows of a table.

Link to code: https://github.com/Leftium/bangtastic/blob/c6d5d6363b0b17e0dada08f96ba91517d1b2d593/src/routes/datatables/%2Bpage.svelte#L47