index.js

// input (x, y)
const weights = [
  [1, 4, 16, 4, 1],
  [4, 16, 24, 16, 4],
  [16, 24, 36, 24, 16],
  [4, 16, 24, 16, 4],
  [1, 4, 16, 4, 1],
];

let blur = 0;
let totalWeight = 0;

for (let i = 0; i < 5; i++) {
  for (let j = 0; j < 5; j++) {
    const weight = weights[i][j];
    
    totalWeight += weight;
    blur += weight * getPixelColor(x + i - 2, y + j -2);
  }
}

blur /= totalWeight;