Contain Virus LeetCode solution in JavaScript

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var containVirus = function (isInfected) {
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  const directions = [
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    [1, 0],
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    [-1, 0],
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    [0, 1],
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    [0, -1],
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  ];
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  let walls = 0;
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  function findContaminated() {
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    let visited = {},
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      infected = [];
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    let mostViral;
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    for (let i = 0; i < isInfected.length; i++) {
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      for (let j = 0; j < isInfected[i].length; j++) {
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        if (isInfected[i][j] === 1) {
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          let key = `${i}-${j}`;
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          if (key in visited) continue;
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          else infected.push([i, j]);
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          let zeroes = new Set();
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          let perimeter = findPerimeter(i, j, visited, zeroes);
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          // Find the largest potential infection perimeter based on the number of 0's neighboring infected cells
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          if (!mostViral) mostViral = { i, j, perimeter, zeroes: zeroes.size };
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          else if (zeroes.size > mostViral.zeroes)
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            mostViral = { i, j, perimeter, zeroes: zeroes.size };
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        }
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      }
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    }
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    if (mostViral) {
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      walls += mostViral.perimeter;
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      // Quarantine the most viral area
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      quarantine(mostViral.i, mostViral.j);
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      // Spread the infection throughout the remaining infected areas
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      let alreadyInfected = {};
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      for (let [row, col] of infected) {
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        if (mostViral.i === row && mostViral.j === col) continue;
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        else infect(row, col, alreadyInfected);
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      }
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      return true;
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    }
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    return false;
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  }
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  while (findContaminated()) continue;
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  return walls;
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  function findPerimeter(row, col, visited, zeroes) {
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    if (
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      row < 0 ||
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      col < 0 ||
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      row >= isInfected.length ||
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      col >= isInfected[0].length
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    )
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      return 0;
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    let key = `${row}-${col}`;
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    // If the current cell is visited or quarantined, leave the perimeter unchanged
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    if (visited[key] || isInfected[row][col] === -1) return 0;
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    // If the current cell is not infected and not quarantined, increase the perimeter
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    if (isInfected[row][col] === 0) {
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      zeroes.add(key);
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      return 1;
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    }
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    visited[key] = true;
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    let perimeter = 0;
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    for (let [r, c] of directions) {
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      perimeter += findPerimeter(row + r, col + c, visited, zeroes);
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    }
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    return perimeter;
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  }
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  function quarantine(row, col) {
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    if (
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      row < 0 ||
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      col < 0 ||
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      row >= isInfected.length ||
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      col >= isInfected[0].length
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    )
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      return;
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    // Only quarantine infected cells and neighboring infected cells
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    if (isInfected[row][col] === 1) isInfected[row][col] = -1;
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    else return;
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    for (let [r, c] of directions) quarantine(row + r, col + c);
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  }
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  function infect(row, col, alreadyInfected, neighbor = 0) {
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    if (
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      row < 0 ||
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      col < 0 ||
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      row >= isInfected.length ||
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      col >= isInfected[0].length
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    )
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      return;
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    let key = `${row}-${col}`;
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    // If the current cell is already infected or quarantined
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    if (alreadyInfected[key] || isInfected[row][col] === -1) return;
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    // If the current cell is clear but neighbors an infected cell, infect it
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    if (isInfected[row][col] === 0 && neighbor === 1) {
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      alreadyInfected[key] = true;
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      return (isInfected[row][col] = 1);
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    } else if (isInfected[row][col] === 1 && neighbor === 1) {
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      alreadyInfected[key] = true;
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      neighbor = 0;
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    }
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    for (let [r, c] of directions)
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      infect(row + r, col + c, alreadyInfected, neighbor + 1);
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  }
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};