Workshop › Battleship › Step 9 of 35

Fire at a square

What we are doing

Your shots are kept in a grid, myShots: null for a square not tried yet, 'miss' or 'hit'. fire shoots at a square of a fleet, writes the result into a grid and returns it.

```js
let myShots // myShots[r][c]: null, 'miss' or 'hit' (on the enemy's sea)

  myShots = grid(null)

// Fire at a square of a fleet and record the result on that shots grid.
function fire(fleet, record, r, c) {
  const ship = shipAt(fleet, r, c)
  if (!ship) {
    record[r][c] = 'miss'
    return 'miss'
  }
  record[r][c] = 'hit'
  return 'hit'
}
```

What it means

reset starts myShots as a grid of null.
fire looks for a ship on the square. None: record and return 'miss'. Otherwise record and return 'hit'.
!ship is true when shipAt gave undefined.

Your turn

Under let myFleet write let myShots with its comment.
In reset, under myFleet = placeFleet(), write myShots = grid(null).
Above function drawSea(, write fire with its comment, followed by an empty line.

Skills: Functions, Arrays and objects

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