DevGod needs to write a blog entry for this problem!

/**
 * @param {number[][]} grid
 * @return {number}
 */
var islandPerimeter = function(grid) {
    let n = grid.length;
    let m = grid[0].length;
    let cnt = 0;
    for (let i = 0; i < n; i++) {
        for (let j = 0; j < m; j++) {
            if (grid[i][j] === 1) {
                if ((j > 0 && grid[i][j - 1] === 0) || j === 0)
                    cnt++;

                if ((i > 0 && grid[i - 1][j] === 0) || i === 0)
                    cnt++;

                if ((j < m - 1 && grid[i][j + 1] === 0) || j === m - 1)
                    cnt++;

                if ((i < n - 1 && grid[i + 1][j] === 0) || i === n - 1)
                    cnt++;
            }
        }
    }
    return cnt;
};