sample.js

var startTime = +new Date();
var shouldDump = false;
var shouldTime = false;

if (state == 'initial') {
    state = {
        idle: 0,
    };
}

// Actions
var none    = 0;
var forward = 1;
var left    = 2;
var right   = 3;

// Lookup table
var table;
if (!table) {
    table = new Uint16Array(80 * 40 * 4);
    table.getAction =  i     => table[i] & 3;
    table.setAction = (i, a) => table[i] |= a;
    table.getNext   =  i     => table[i] >> 2;
    table.setNext   = (i, n) => table[i] |= n << 2;
} else {
    table.fill(0);
}
table.head = 0;
table.tail = 0;

// Main function
var level0 = getLevel();
var dir0 = getDirection();
var [x0, y0] = getPosition();
var [x1, y1] = getExitPosition();

state.idle++;
if (level0 == 2 && state.idle >= 4) {
    moveForwardMaybe();
}
else search();

// Index calculations
function pack(y, x, dir) {
    return (y * 80 + x) * 4 + dir;
}

function unpack(i) {
    let dir = i & 3;
    i >>= 2;
    let x = i % 80;
    i /= 80;
    let y = i |0;
    return [y, x, dir];
}

// Queue
function enqueue(i) {
    table.setNext(table.tail, i);
    table.tail = i;
}

function dequeue() {
    return table.head = table.getNext(table.head);
}

// Search
function search() {
    for (let dir = 0; dir < 4; dir++) {
        visit(y1, x1, dir, forward);
    }
    while (true) {
        if (table.head == table.tail) break;
        let [y, x, dir] = unpack(dequeue());
        if (y == y0 && x == x0 && dir == dir0) break;
        visit(y, x, (dir + 1) % 4, left);
        visit(y, x, (dir + 3) % 4, right);
        let [dy, dx] = [[1, 0], [0, -1], [-1, 0], [0, 1]][dir];
        if (!isBlocked(y + dy, x + dx)) {
            visit(y + dy, x + dx, dir, forward);
        }
    }
    let a = table.getAction(pack(y0, x0, dir0));
    [giveUp, moveForwardMaybe, turnLeft, turnRight][a]();
}

function visit(y, x, dir, a) {
    let i = pack(y, x, dir);
    if (table.getAction(i)) return;
    table.setAction(i, a);
    enqueue(i);
}

function isBlocked(y, x) {
    let pos = [x, y];
    let char = whatsAt(pos);
    if (char == '#') return true;
    if (!'^>v<'.includes(char)) return false;
    if (x == x0 && y == y0) return false;
    if (Math.abs(x - x0) + Math.abs(y - y0) > 5) return false;
    return isProtected(pos);
}

function giveUp() {
    console.log('No path found!');
    moveForwardMaybe();
}

function moveForwardMaybe() {
    let newPos = movePos([x0, y0], dir0);
    if (whatsAt(newPos) == '#') {
        turnRight();
        return;
    }
    if (!isProtected(newPos)) {
        for (let dir of [3, 0, 1]) {
            let enemyPos = movePos(newPos, (dir0 + dir) % 4);
            let enemyDir = '^>v<'.indexOf(whatsAt(enemyPos));
            if (enemyDir >= 0) {
                let [ex, ey] = movePos(enemyPos, enemyDir);
                if (ex == newPos[0] && ey == newPos[1]) return;
            }
        }
    }
    moveForward();
    state.idle = 0;
}

function movePos(pos, dir) {
    let d = [[0, -1], [1, 0], [0, 1], [-1, 0]][dir];
    return [pos[0] + d[0], pos[1] + d[1]];
}

function dumpTable(dir) {
    for (let y = 39; y >= 0; y--) {
        let line = '';
        for (let x = 0; x < 80; x++) {
            let a = table.getAction(pack(y, x, dir));
            line += ' .<>'[a];
        }
        console.log(line);
    }
}

if (shouldDump) dumpTable(dir0);
if (shouldTime) {
    let endTime = +new Date();
    let timeTaken = endTime - startTime;
    console.log(`Executed in ${timeTaken / 1000} seconds.`);
}