CodeSignal - Arcade - Intro - JS - Box Blur

Box Blur.js

function boxBlur(image) {
    let bluredImage = Array.from(Array(image.length-2), () => new Array(image[0].length-2));

    for(let i = 1; i < image.length-1; i++) {
        for(let j = 1; j < image[i].length-1; j++){
            
            bluredImage[i-1][j-1] = Math.floor((
                    image[i-1][j-1] + image[i-1][j] + image[i-1][j+1] +
                    image[i][j-1]   + image[i][j]   + image[i][j+1]   +
                    image[i+1][j-1] + image[i+1][j] + image[i+1][j+1]
                )/9);
        }
    }
    
    return bluredImage;
}