Grid Illumination LeetCode solution in JavaScript

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var gridIllumination = function (n, lamps, queries) {
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  const directions = [
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    [0, 0],
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    [-1, -1],
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    [-1, 0],
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    [-1, 1],
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    [0, -1],
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    [0, 1],
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    [1, -1],
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    [1, 0],
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    [1, 1],
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  ];
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  const lampCoord = new Map();
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  const rowHash = {},
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    colHash = {},
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    leftDiag = {},
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    rightDiag = {};
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  // First, illuminate the lamps
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  for (let [r, c] of lamps) {
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    if (lampCoord.has(`${r}-${c}`)) continue;
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    lampCoord.set(`${r}-${c}`);
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    rowHash[r] = rowHash[r] + 1 || 1;
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    colHash[c] = colHash[c] + 1 || 1;
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    leftDiag[r + c] = leftDiag[r + c] + 1 || 1;
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    rightDiag[c - r] = rightDiag[c - r] + 1 || 1;
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  }
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  // Second, query the lamps
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  let output = [];
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  for (let [row, col] of queries) query(row, col);
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  return output;
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  function query(row, col) {
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    if (
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      rowHash[row] ||
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      colHash[col] ||
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      leftDiag[row + col] ||
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      rightDiag[col - row]
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    ) {
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      output.push(1);
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      // Check 8 adjacent cells
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      for (let [r, c] of directions) {
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        let newR = row + r,
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          newC = col + c;
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        if (newR < 0 || newC < 0 || newR >= n || newC >= n) continue;
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        // If the coordinate is a lamp, un-illuminate the lamp
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        if (lampCoord.has(`${newR}-${newC}`)) {
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          rowHash[newR]--,
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            colHash[newC]--,
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            leftDiag[newR + newC]--,
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            rightDiag[newC - newR]--;
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          lampCoord.delete(`${newR}-${newC}`);
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        }
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      }
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    } else output.push(0);
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  }
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};