Recursive function (maze solver) - can't find a bug;(((

I am studying javascript and all is pretty easy to me except for some things like recursive functions. I do understand the way they work but while working with an example, I realized I can't capture the bug that prevents it from functioning...

I have an array (map) below (0 is a closed cell, 1 means path is open) and the recursive function I am trying to use to "find" path out of this "maze" by going from its top left cell to the bottom-right one.. Basically just make the function to "find" this path of 1s. But it fails;(

var map = [
        [1,1,0,0],
        [0,1,1,0],
        [0,0,1,0],
        [0,0,1,1]
    ]

function findpath(x,y) {
    if (x<0 || x>3 || y<0 || y>3) return false; //if it is outside of map
    if (x==3 && y==3) return true; // if it is the goal (exit point)
    if (map[y][x]==0) return false; //it is not open
    map[y][x]=9; //here marking x,y position as part of solution path outlined by "9"
    if (findpath(x,y-1) == true) return true;
    if (findpath(x+1,y) == true) return true;
    if (findpath(x,y+1) == true) return true;
    if (findpath(x-1,y) == true) return true;
    map[y][x]=8; //unmark x,y as part of solution path outlined by "8"
    return false;
    };
findpath(0,0);

Solution

Quick answer:

Its locking in a loop because the order of the checks.

Start from 0:0 then try 0:1. Then from 0:1 --"Ummm... 0:0 looks promising. Let's go there". So go back to 0:0... so it locks... Try leaving backtracking last :

if(findpath(x+1,y)) return true;    
if(findpath(x,y+1)) return true;    
if(findpath(x,y-1)) return true;
if(findpath(x-1,y)) return true;

This get you out of the lock just by swapping the issue around. If you start from 3:3 trying to reach 0:0 you'll be locked again. Whats missing its a way to mark visited squares.

I think you are trying to implement an a* algorithm

UPDATE:

Here is your idea working. Just added the backtracking checks you almost implemented.

<html>
    <head>
    </head>
    <body>
        <script>
            var map = [
            [1,1,0,0],
            [0,1,1,0],
            [1,1,1,0],
            [1,0,1,1]
        ]
        
    var goalx = 0;
    var goaly = 3;
    
    console.log();
    
    function findpath(x,y) {
        
        
        // illegal move check
        if (x < 0 || x > (map[0].length -1) || y < 0 || y > (map.length - 1)) return false; //if it is outside of map
        if (map[y][x]==0) return false; //it is not open
        
        // end move check
        if (x== goalx && y== goaly){
            console.log('Reached goal at: ' + x + ':' + y);
            return true; // if it is the goal (exit point)
        }
        
        if(map[y][x] == 9 || map[y][x] == 8)
            return false;
        
        console.log('Im here at: ' + x + ':' + y);
        
        map[y][x]=9; //here marking x,y position as part of solution path outlined by "9"
        
        if(findpath(x+1,y)) 
            return true;    
        if(findpath(x,y+1)) 
            return true;    
        if(findpath(x,y-1))
            return true;
        if(findpath(x-1,y)) 
            return true;                    
        
        map[y][x]=8; //unmark x,y as part of solution path outlined by "8"
        
        return false;
    };
    
    findpath(3, 3);
        </script>
    </body>
</html>