Performance is not a problem, not a language like JS, Ruby or whatnot. Therefore, we can only think about code readability. And this case is not strongly related to JS, so my examples will be.
move = ["E2", "E4"];
if chessboard.valid(move, player) {
...
}
: " (E2 E4), ...", , . , , ( , ):
if chessboard.valid(["E2", "E4"], player) {
...
}
? valid ? , , ? , , , . , . , , chessboard:
if chessboard.valid_move(["E2", "E4"], player) {
...
}
, API, - .
, :