JSFiddle - React, Tailwind, and code Playground
JavaScript
const data = [
[{ id : 1}, { id: 4 }],
[{ id :2 }, { id : 3}]
]
const findIJ = ( data, id ) =>
data.reduce( (p, c, i) => {
let j = data[i].findIndex( x => x.id === id );
if( j > - 1){
return { i, j }
}
return p;
}, { i : -1, j : -1 });
console.log( findIJ( data, 1 ) );
console.log( findIJ( data, 3 ) );
console.log( findIJ( data, 5 ) );