I personally haven't seen anything else this readable.

```
const islandPerimeter = grid => {
var perimeter = 0
const isWater = val => !val
const isLand = val => val === 1
for (let y = 0; y < grid.length; y++) {
for (let x = 0; x <= grid[y].length; x++) {
var curr = grid[y][x]
if (isLand(curr)) {
var top = grid[y - 1] && grid[y - 1][x]
var bottom = grid[y + 1] && grid[y + 1][x]
var left = grid[y][x - 1]
var right = grid[y][x + 1]
if (isWater(top)) perimeter++
if (isWater(bottom)) perimeter++
if (isWater(left)) perimeter++
if (isWater(right)) perimeter++
}
}
}
return perimeter
};
```