codewar, rook moves

https://www.codewars.com/kata/chess-fun-number-12-possible-rook-moves/train/javascript

function possibleRookMoves(b, square, flag) {
			const letter = square[0].toLowerCase(),
				letterNum = letter.charCodeAt(0) - 97,
				num = b.length - square[1],
				arrayNum = num + 1,
				enemy = flag === 1 ? -1 : 1,
				ally = flag === 1 ? 1 : -1;
			const row = definePosition(b[num],'hor', letterNum)
			const col = definePosition(b, 'vert', num, letterNum)

			return [].concat(
				filterMoves(col, 'vert'),
				filterMoves(row, 'hor'))
				.sort()

			function definePosition(arr, mode, num1, num2) {
				return arr.map((e, i) => {
					if(mode === 'vert') e = e[num2];
					if (i === num1) return 'rook';
					if (e === 0) return true;
					if (e === enemy) return 'enemy';
					return 'ally'
				})
			}

			function filterMoves(arr, mode) {
				let rookOccured = false;
				let isEnd = false;
				let move;
				const moves = [];
				arr.forEach((e, i) => {
					if (isEnd) return;
					//here is const move = letter + (col.length - i);
					if (mode === 'hor') move = String.fromCharCode(i + 97) + square[1];
					if (mode === 'vert') move = letter + (col.length - i);
					if (e === true && !rookOccured)
						return moves.push(move);
					if (e === 'enemy' && !rookOccured)
						return moves.splice(0, moves.length, move);
					if (e === 'ally' && !rookOccured)
						return moves.splice(0, moves.length);
					if (e === 'rook')
						return rookOccured = true;
					if (e === 'ally' && rookOccured) return isEnd = true;
					if (e === true && rookOccured) return moves.push(move);
					if (e === 'enemy' && rookOccured) {
						isEnd = true;
						return moves.push(move)
					}
				})
				return moves
			}
		}

		console.log(possibleRookMoves([
			[0, 1, 0, -1, 0],
			[0, 0, -1, 0, 0],
			[0, 0, 0, 0, 0],
			[0, 0, 0, 0, 0],
			[-1, 0, 1, 1, 0]], "c5", 1), ["c4", "d5"])

/* 		console.log(possibleRookMoves([
			[1, -1, 1, 0],
			[1, 0, 1, 1],
			[1, -1, 0, 0],
			[0, 0, -1, 0]], "b1", 1), ["a1", "c1"])

		console.log(possibleRookMoves([
			[0, 0, 0],
			[0, 0, 0],
			[0, 1, 0]], "b2", 1), ["a2", "b3", "c2"])

		console.log(possibleRookMoves([
			[0, 1, 0, -1, 0],
			[0, 0, -1, 0, 0],
			[0, 0, 0, 0, 0],
			[0, 0, 0, 0, 0],
			[-1, 0, 1, 1, 0]], "c5", 1), ["c4", "d5"])

		console.log(possibleRookMoves([
			[0, 1, 0],
			[0, -1, -1],
			[0, 1, 0]], "a2", 1), ["a1", "a3", "b2"])

		console.log(possibleRookMoves([
			[0, 0, 1, 0],
			[1, 1, 0, 1],
			[0, 0, 1, 0],
			[0, 0, 1, 0]], "c3", -1), ["b3", "c2", "c4", "d3"])

		console.log(possibleRookMoves([
			[0, 1, 0],
			[1, 0, 1],
			[0, 1, 0]], "b2", -1), ["a2", "b1", "b3", "c2"])

		console.log(possibleRookMoves([
			[0, 1, 0],
			[1, 0, 1],
			[0, 1, 0]], "b2", 1), [])