Solution to level 13 in Untrusted: http://alex.nisnevich.com/untrusted/

untrusted-lvl13-solution.js

/*
 * robotMaze.js
 *
 * The blue key is inside a labyrinth, and extracting
 * it will not be easy.
 *
 * It's a good thing that you're a AI expert, or
 * we would have to leave empty-handed.
 */

function startLevel(map) {
    // Hint: you can press R or 5 to "rest" and not move the
    // player, while the robot moves around.

    map.getRandomInt = function(min, max) {
        return Math.floor(Math.random() * (max - min + 1)) + min;
    }

    map.placePlayer(map.getWidth()-1, map.getHeight()-1);
    var player = map.getPlayer();

    map.defineObject('robot', {
        'type': 'dynamic',
        'symbol': 'R',
        'color': 'gray',
        'onCollision': function (player, me) {
            me.giveItemTo(player, 'blueKey');
        },
        'behavior': function (me) {
            var moves = map.getAdjacentEmptyCells(me.getX(), me.getY());
            if (me.direction === undefined) {
                me.direction = 'right';
                me.D = {
                    'right':{r:'down',  l:'up',    dx:  1, dy: 0 },
                    'down' :{r:'left',  l:'right', dx:  0, dy: 1 },
                    'left' :{r:'up',    l:'down',  dx: -1, dy: 0 },
                    'up'   :{r:'right', l:'left',  dx:  0, dy: -1}
                };
                //map.writeStatus(me.direction);
                
                me.getObjectTypeInFront = function() {
                    var x = me.getX()+me.D[me.direction].dx;
                    var y = me.getY()+me.D[me.direction].dy;
                    return map.getObjectTypeAt(x, y);
                };
                
                me.turnRight = function() {
                    me.direction = me.D[me.direction].r;
                };
                
                me.turnLeft = function() {
                    me.direction = me.D[me.direction].l;
                };
                
                me.canMoveForward = function() {
                    var moves = map.getAdjacentEmptyCells(me.getX(), me.getY());
                    var res = moves.some(function(v, k, arr){
                        return v[1] == me.direction;
                    });
                    if (!res) {
                        var type = me.getObjectTypeInFront()
                        res = (type == 'blueKey') || (type == 'barrier');
                    }
                    return res;
                };
                
                me.isHoleOnLeft = function() {
                    var moves = map.getAdjacentEmptyCells(me.getX(), me.getY());
                    return moves.some(function(v, k, arr){
                        return v[1] == me.D[me.direction].l;
                    });                    
                };
            }
            if (me.isHoleOnLeft()) {
                me.turnLeft();
                me.move(me.direction);
            }
            else if (!me.canMoveForward()) {
                me.turnRight();
            }
            else {
                me.move(me.direction);
            }
            map.writeStatus(me.direction);


        }
    });

    map.defineObject('barrier', {
        'symbol': '░',
        'color': 'purple',
        'impassable': true,
        'passableFor': ['robot']
    });

    map.placeObject(0, map.getHeight() - 1, 'exit');
    map.placeObject(1, 1, 'robot');
    map.placeObject(map.getWidth() - 2, 8, 'blueKey');
    map.placeObject(map.getWidth() - 2, 9, 'barrier');

    var autoGeneratedMaze = new ROT.Map.DividedMaze(map.getWidth(), 10);
    autoGeneratedMaze.create( function (x, y, mapValue) {
        // don't write maze over robot or barrier
        if ((x == 1 && y == 1) || (x == map.getWidth() - 2 && y >= 8)) {
            return 0;
        } else if (mapValue === 1) { //0 is empty space 1 is wall
            map.placeObject(x,y, 'block');
        } else {
            map.placeObject(x,y,'empty');
        }
    });
}

function validateLevel(map) {
    map.validateExactlyXManyObjects(1, 'exit');
    map.validateExactlyXManyObjects(1, 'robot');
    map.validateAtMostXObjects(1, 'blueKey');
}

function onExit(map) {
    if (!map.getPlayer().hasItem('blueKey')) {
        map.writeStatus("We need to get that key!");
        return false;
    } else {
        return true;
    }
}