1var assert = require('assert');
2
3function shortestClearPath(grid) {
4    let m = grid.length;
5    let n = grid[0].length;
6
7    if (grid[0][0] === 1 || grid[m - 1][n - 1] === 1) {
8        return -1;
9    }
10
11    let directions = [
12        [0, 1],
13        [0, -1],
14        [1, 0],
15        [-1, 0],
16        [1, 1],
17        [1, -1],
18        [-1, 1],
19        [-1, -1]
20    ];
21
22    let queue = [
23        [
24            [0, 0], 1
25        ]
26    ];
27    grid[0][0] = 1;
28
29    while (queue.length > 0) {
30        let [cellPosition, pathLength] = queue.shift();
31        let x = cellPosition[0];
32        let y = cellPosition[1];
33
34        if (x === m - 1 && y === n - 1) {
35            return pathLength;
36        }
37
38        // otherwise we have to go 8 directions
39        for (const direction of directions) {
40            let newX = x + direction[0];
41            let newY = y + direction[1];
42
43            // check if we are on valid tile
44            if (newX >= 0 && newX < m && newY >= 0 && newY < n && grid[newX][newY] === 0) {
45                queue.push([
46                    [newX, newY], pathLength + 1
47                ]);
48                grid[newX][newY] = 1;
49            }
50        }
51    }
52    return -1;
53
54}
55
56
57try {
58    assert.equal(shortestClearPath([
59        [0, 1],
60        [1, 0]
61    ]), 2);
62    console.log('PASSED: ' + "`shortestClearPath([[0,1],[1,0]])` should return `2`");
63} catch (err) {
64    console.log(err);
65}
66
67try {
68    assert.equal(shortestClearPath([
69        [0, 0, 0],
70        [1, 1, 0],
71        [1, 1, 0]
72    ]), 4);
73    console.log('PASSED: ' + "`shortestClearPath([[0,0,0],[1,1,0],[1,1,0]])` should return `4`");
74} catch (err) {
75    console.log(err);
76}
77
78try {
79    assert.equal(shortestClearPath([
80        [1, 0, 0],
81        [1, 1, 0],
82        [1, 1, 0]
83    ]), -1);
84    console.log('PASSED: ' + "`shortestClearPath([[1,0,0],[1,1,0],[1,1,0]])` should return `-1`");
85} catch (err) {
86    console.log(err);
87}