MultiplayerMinesweeper/scripts/world/revealer.mjs

const searchLoc =
[
  [-1,1], [0,1], [1,1],
  [-1,0],        [1,0],
  [-1,-1],[0,-1],[1,-1]
]

export function reveal(x, y, data) {
  if (data[x][y].type !== 5) {

    var toSearch = [];
    var searchedLocations = [];
    toSearch.push([x, y])

    if (data[x][y].type === 1) {
    while (toSearch.length > 0) {
            const x = toSearch[0][0]
            const y = toSearch[0][1]
            searchedLocations.push(toSearch[0])
            toSearch.shift()
            searchLoc.forEach(loc => {
            const tempx = x + loc[0]
            const tempy = y + loc[1]
            if (tempx >= 0 && tempy >= 0 && tempx < data.length && tempy < data[0].length) {

              if (data[tempx][tempy].type === 1 && data[tempx][tempy].mask === true) {

                if (!toSearch.includes([tempx,tempy]) && !searchedLocations.includes([tempx,tempy])) {
                  toSearch.push([tempx,tempy])
                }
              }
            if (data[tempx][tempy].type !== 5) {
              data[tempx][tempy].mask = false;
            }
          }
          })

      }
    }
      return data
  }
}